JPH07164591A - Laminated film of gas barrier properties - Google Patents

Abstract

PURPOSE:To provide a laminated film of gas barrier properties having flexibility, super gas barrier properties to oxygen, water vapor and the like, resistance to heat, resistance to humidity and water resistance, and easy to manufacture. CONSTITUTION:A deposited layer 3 composed of an inorganic compound is formed as a first layer on a base 2 composed of a polymer resin composition, and a coating agent as an agent containing a water solution which contains a water-soluble polymer and also contains at least one kind of either of (a) metallic alcoxide or its hydrolyzate of one kind or more or (b) tin chloride, or the coating agent composed of water/alcohol mixed solution, is applied thereon, and heat dried film 4 of gas barrier properties is laminated thereon as a second layer to provide a film of superior gas barrier properties, of water resistance and of humidity resistance, which can be flexible enough for the deformation to a certain extent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas barrier laminate used in the field of packaging foods, pharmaceuticals and the like.

[0002]

2. Description of the Related Art In recent years, packaging materials used for packaging foods, pharmaceuticals, etc. are used to suppress deterioration of contents, particularly oxidation and deterioration of proteins, fats and oils in foods, and to maintain taste and freshness. In addition, in the case of pharmaceuticals that require aseptic handling, the effects of oxygen, water vapor and other gases that permeate the packaging material are prevented in order to prevent deterioration of the active ingredient and maintain efficacy. Therefore, it is required to have a gas barrier property of blocking these gases.

Therefore, conventionally, it is generally said that polyvinyl alcohol (hereinafter referred to as PVA), ethylene vinyl alcohol copolymer (EVOH), polyvinylidene chloride resin (hereinafter referred to as PVDC), etc. has relatively high gas barrier properties. A packaging film used as a packaging material as a gas barrier laminate by laminating or coating a polymer resin composition has been generally used. In addition, a metal-deposited film obtained by vapor-depositing a metal or a metal compound such as Al on a suitable polymer resin composition (even a resin that does not have a high gas barrier property alone), and recently silicon monoxide (SiO) Vapor-deposited films formed by forming means such as vapor-deposition of a silicon oxide (SiO _x ) thin film and a magnesium oxide (MgO) thin film on a substrate made of a transparent polymer material have been developed. It has superior gas barrier properties to a gas barrier material composed of a polymer resin composition, is less likely to deteriorate under high humidity, and packaging films used as packaging materials have begun to be generally used.

[0004]

However, the PV described above is used.
Since the gas barrier laminate using the A and EVOH-based polymer resin compositions has large temperature dependence and humidity dependence, the gas barrier properties are deteriorated at high temperature or high humidity, and particularly the water vapor barrier property is exhibited. However, depending on the application of the packaging, the gas barrier property may be significantly lowered when the boiling treatment or the retort treatment is performed. A gas barrier laminate using a PVDC-based polymer resin composition has a small humidity dependency, but has an oxygen barrier property of 1 cm ³ / m ² · day · a.
It is difficult to realize a high gas barrier material (high gas barrier material) of tm or less. In addition, since the coating contains a large amount of chlorine, there is a problem in terms of waste treatment such as incineration and recycling.

Further, the above-mentioned metal vapor-deposited film vapor-deposited with a metal or metal compound, silicon oxide thin film such as silicon monoxide (SiO), vapor-deposited film magnesium oxide (MgO) thin film are inorganic compounds used for gas barrier layers. The film is lacking in flexibility, is weak against rubbing and bending, and has poor adhesion to the base material, so care must be taken when handling it, especially when post-processing packaging materials such as printing, laminating and bag making. In addition, there is a problem that cracks are generated and the gas barrier property is significantly deteriorated. Further, since the forming method is performed by using a vacuum process such as a vacuum vapor deposition method, a sputtering method, and a plasma chemical vapor deposition method, the apparatus is expensive, and the temperature becomes high locally at the forming step, which may damage the base material. In some cases, defects, pinholes, etc. may occur in the inorganic thin film due to decomposition or degassing of low molecular weight parts or additive parts such as plasticizers, etc., high gas barrier property cannot be achieved, cost There is a problem that it becomes expensive.

Therefore, in order to solve the above problems, Japanese Patent Laid-Open No. 62-62
As described in JP-A-295931, a gas barrier material has been proposed in which a metal alkoxide coating film is formed on a base material. Since this gas barrier material has a certain degree of flexibility and can be manufactured by the liquid phase coating method, the cost can be reduced.

However, although the gas barrier material can be said to have an improved gas barrier property as compared with the case where the base material alone is used, it cannot be said to have an absolute gas barrier property.

Further, as described in JP-A-5-9317, as a method for producing a resin molded product having a gas barrier property, a vapor-deposited thin film of silicon oxide (SiO _x ) is formed on a substrate, and A method has been proposed in which a vapor-deposited thin film is coated with a mixed solution of SiO ₂ particles and a water-soluble resin or an aqueous emulsion and then dried. The resin molded product produced by this manufacturing method is
A mixed layer of SiO ₂ particles and a resin coated on the O _X vapor-deposited thin film suppresses the spread of microcracks generated in the SiO _X vapor-deposited thin film and protects the cracked portion, thereby suppressing the deterioration of the gas barrier property. It is a thing. However, the resin molded product with this configuration is
It only suppresses the spread of microcracks generated in the SiO _x evaporated thin film and suppresses the deterioration of the gas barrier property, and the effect is merely a role as a protective layer of the evaporated thin film. The gas-barrier property of the resin molded product having the above-mentioned configuration shows the gas-barrier property of a vapor-deposited film in which a vapor-deposited thin film is simply formed on a substrate because the coating layer formed on the vapor-deposited layer is a simple mixed coating of SiO ₂ particles and resin However, it was impossible to obtain a higher gas barrier property.

Therefore, the present invention provides a gas barrier laminate film which is flexible and has an excellent gas barrier property against oxygen, water vapor and the like, has heat resistance, moisture resistance and water resistance and is easy to manufacture. With the goal.

[0010]

The invention according to claim 1 is
A vapor deposition layer made of an inorganic compound is used as a first layer on a base material made of a polymer resin composition, and a water-soluble polymer, (a) one or more metal alkoxides and hydrolysates thereof, or (b) tin chloride. A gas-barrier laminated film, characterized by comprising a second layer of a gas-barrier coating formed by applying a coating agent containing an aqueous solution containing at least one of is there.

The invention according to claim 2 is the gas barrier laminated film according to claim 1, wherein the water-soluble polymer is polyvinyl alcohol based on the invention according to claim 1.

The invention according to claim 3 is based on the invention according to claim 1, wherein the metal alkoxide is tetraethoxysilane or triisopropoxyaluminum, or a mixture thereof, in a gas barrier laminate film. is there.

The invention according to claim 4 is based on the invention according to claim 1, characterized in that the vapor deposition layer comprising an inorganic compound is any one of aluminum oxide, magnesium oxide, tin oxide and silicon oxide. Laminated film.

[0014]

According to the present invention, a vapor deposition layer made of an inorganic compound is used as a first layer on a substrate made of a polymer resin composition, a water-soluble polymer, and (a) one or more metal alkoxides and A gas barrier coating formed by applying a coating agent containing an aqueous solution containing at least one of a hydrolyzate or (b) tin chloride or a water / alcohol mixed solution as a main component and heating and drying as a second layer. As a result, since the second layer contains a highly reactive inorganic component and the composite coating with the water-soluble polymer has excellent gas barrier properties, will both reaction layers be formed at the interface between the first layer and the second layer? , Or the second layer is the first
By filling and reinforcing pinholes, cracks, grain boundaries, and other defects or micropores that occur in the layer, a dense structure is formed, so it has high gas barrier properties, water resistance, moisture resistance, and can withstand deformation. It has flexibility.

[0015]

EXAMPLE An example of the present invention will be described in detail. FIG. 1 is a schematic diagram illustrating the structure of the gas barrier laminate of the present invention.

In FIG. 1, reference numeral 1 denotes a gas barrier laminate, which is a substrate 2, an inorganic vapor deposition layer 3 as a first layer, and a gas barrier coating layer 4 as a second layer. The substrate 2 is in the form of a sheet or a film, and is made of polyolefin (polyethylene, polypropylene, etc.), polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyamide (Nelon-
6, nylon-66, etc.), polyvinyl chloride, polyimide, etc., or those commonly used as packaging materials such as copolymers of these polymers can be used. The base material is appropriately selected from the above materials according to the application.

The polymer resin material used for the base material 2 includes, for example, an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant,
Known additives such as colorants can be added, and they are appropriately added as necessary.

Further, the surface of the substrate 2 may be subjected to surface modification such as corona treatment and anchor coat treatment to improve the adhesion of the coating.

The first inorganic vapor deposition layer 3 is made of oxides, nitrides or fluorides of silicon, aluminum, titanium, zirconium, tin, magnesium or the like, or a composite thereof, and is vacuum deposited. It is formed by a vacuum process such as a sputtering method or a plasma vapor deposition method (CVD method). In particular, aluminum oxide is colorless and transparent and has excellent characteristics such as resistance to boiling and retort, and can be used in a wide range of applications.

The thickness of the inorganic vapor-deposited layer 3 varies depending on the application and the thickness of the second layer, but is preferably in the range of several tens Å to 5,000 Å, but below 50 Å there is a problem with the thin film continuity.
Further, when it exceeds 3000 Å, cracks are likely to occur and flexibility is lowered, so that it is preferably 50 to 3000 Å.

The gas barrier coating layer 4, which is the second layer, is an aqueous solution containing a water-soluble polymer and at least one of (a) at least one metal alkoxide and its hydrolyzate or (b) tin chloride, or water. / Coating agent consisting mainly of alcohol solution. The base material is a solution in which a water-soluble polymer and tin chloride are dissolved in a water-based (water or water / alcohol mixed) solvent, or a solution in which a metal alkoxide is directly or previously hydrolyzed. 2 is coated on the inorganic thin film layer 3, heated and dried,
It was formed. Each component contained in the coating agent will be described in detail below.

The water-soluble polymer used in the coating agent of the present invention includes polyvinyl alcohol, polyvinylpyrrolidone, starch, methyl cellulose, carboxymethyl cellulose, sodium alginate, etc. In particular, polyvinyl alcohol (hereinafter referred to as PVA) is used in the present invention. The gas barrier property is most excellent when used as a coating agent for a gas barrier laminate. PVA here is
Generally obtained by saponification of polyvinyl acetate, so-called partially saponified PVA in which several tens% of acetic acid groups remain.
Saponified PVA with only a few percent of acetic acid groups remaining
Up to and including, but not limited to.

Further, tin chloride is stannous chloride (SnCl ₂ ),
It may be stannic chloride (SnCl ₄ ), or a mixture thereof, and either anhydrous or hydrated can be used.

The metal alkoxide is a general formula such as tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ ] or triisopropoxyaluminum [Al (O-2′-C ₃ H ₇ ) ₃ ], M (OR). _n (M: Si Ti Ai Zr or other metal _, R: CH ₃ ,
And an alkyl group such as C ₂ H ₅ ). Of these, tetraethoxysilane and triisopropoxyaluminum are preferable because they are relatively stable in an aqueous solvent after hydrolysis.

Each of the above-mentioned components can be added to the coating agent alone or in combination, and the isocyanate compound, the silane coupling agent, the dispersant or the stabilizer can be added as long as the barrier properties of the coating agent are not impaired. Well-known additives such as a viscosity modifier and a colorant can be added.

For example, the isocyanate compound added to the coating agent has two or more isocyanate groups (NCO groups) in its molecule. For example, tolylene diisocyanate (hereinafter referred to as TDI) and triphenylmethane triisocyanate. (Hereinafter, referred to as TTI), tetramethyl xylene diisocyanate (hereinafter, referred to as TTI)
TMXDI) and their polymers and derivatives.

As a coating method of the coating agent, conventionally known means such as a dipping method, a roll coating method, a screen printing method and a spraying method which are usually used can be used. Although the thickness of the coating varies depending on the type of coating agent, the thickness after drying may be in the range of about 0.01 to 100 μm. It is desirable to set it to 50 μm.

Although the details are often unclear, some kind of reaction layer is formed between the inorganic vapor-deposited layer 3 as the first layer and the coating film made of the coating agent as the second layer, or The second layer fills and reinforces defects or fine pores such as pinholes, cracks, and grain boundaries generated in the first layer to form a dense structure, which improves the gas barrier property and is a vapor deposition thin film layer that is the first layer. Plays the role of a protective layer. Moreover, since the composition of the coating agent is mainly composed of an inorganic component composed of a metal alkoxide or tin chloride and a water-soluble polymer such as PVA, the gas barrier property can be improved. That is, an inorganic component composed of metal alkoxide or tin chloride is hydrolyzed in a solution,
A polycondensation reaction is performed to form a chain-like or three-dimensional dendritic polymer, and the polymerization proceeds further by evaporation of the solvent accompanied by drying and heating. It is a highly reactive inorganic component. It is considered to form a complex. Therefore, silica (SiO 2) having a specific particle size is used.
₂ ) and other fine particles, and silica sol (colloidal silica) obtained from sodium silicate (water glass) are simply different from those in which fine particles are dispersed.

Further, on the gas barrier laminate of the present invention, a thermoplastic resin layer capable of being heat-sealed, if necessary,
The printing layer can be laminated on the gas barrier coating layer or the substrate 2, and it is also possible to laminate a plurality of resins via an adhesive layer.

The gas barrier laminate of the present invention will be described with reference to specific examples.

Example 1 A film was formed by a vacuum evaporation method using an electron beam heating method, using a substrate of polyethylene terephthalate (hereinafter referred to as PET) having a thickness of 12 μm, and using SiO (silicon oxide) as an evaporation source on its upper surface. A thin film layer with a thickness of 400Å is formed, and the coating composition prepared by combining the following compositions and mixing in a predetermined ratio is applied by a bar coater and dried at 120 ° C for 1 minute to give a film thickness of about 0.3 μm.
Was formed to obtain a gas barrier laminate.

(Component of Coating Agent) (A) Tetraethoxysilane [Si (OC ₂ H ₅ ) ₄ :
Hereinafter referred to as TEOS] 10.4 g of hydrochloric acid (0.1 N)
A hydrolyzed solution having a solid content of 3 wt% (converted to SiO ₂ ) obtained by adding 89.6 g and stirring for 30 minutes to hydrolyze. (B) Triisopropoxy aluminum [Al (O-
2′-C ₃ H ₇ ) ₃ : hereinafter referred to as TPA] 6.0 g was dissolved in 90 g of hot water at 80 ° C., and then 4 g of hydrochloric acid (5N) was added.
3% by weight of solid content obtained by adding and deflocculating (as Al ₂ O ₃ )
Hydrolysis solution of (C) Stannous chloride (anhydrous) 3 wt% water / ethanol solution (water: ethanol weight ratio 50:50) (D) Stannous chloride (anhydrous) 3 wt% aqueous solution (E) 3.0 wt% polyvinyl alcohol water / isopropyl alcohol solution (water: isopropyl alcohol weight ratio 90:10) (F) Polyvinylpyrrolidone 3 wt% water / ethanol solution (water: ethanol weight ratio 50:50 ) (G) Water-based gravure ink (acrylic) Only water-based vehicle is used. Acrylic resin solid content 10 wt% water / ethanol solution (water: ethanol weight ratio 50:50) (H) 3.0 w of silica fine particles (average particle size 0.1 μm)
t% aqueous dispersion (I) 3.0 wt% silica sol solution obtained by diluting silica sol (trade name: Snowtex, manufactured by Nissan Chemical Industries, Ltd.) with water.

(Composition of Coating Agent) Example No. 1 (A) / (E) Compounding ratio (wt%) 60/40 Example No. 2 (A) / (B) / (F) compounding ratio (wt%) 50/10/40 Example No. 3 (C) / (E) Compounding ratio (wt%) 60/40 Example No. 4 (A) / (C) / (E) compounding ratio (wt%) 40/30/30 Example No. 5 (A) / (D) / (E) compounding ratio (wt%) 40/30/30 Comparative Example No. 6 No coating Compounding ratio (wt%) Comparative example No. 7 (E) Compounding ratio (wt%) 100 Comparative example No. 8 (F) Compounding ratio (wt%) 100 Comparative example No. 9 (G) Compounding ratio (wt%) 100 Comparative example No. 10 (H) / (E) Compounding ratio (wt%) 60/40 Comparative Example No. 11 (I) / (E) compounding ratio (wt%) 60/40

The gas barrier laminate thus obtained was placed at 40 ° C.-9.
It was stored under a constant temperature and humidity of 0% RH for 4 weeks, and the gas barrier properties before and after the storage were evaluated by measuring oxygen permeability and water vapor permeability. Oxygen barrier property was measured under an atmosphere of 25 ° C and 100% RH.
CON OXTRAN 10 / 40A) to measure the water vapor barrier property in an atmosphere of 40 ° C.-90 RH (Perrm made by Modern Control Co., Ltd.).
Measurement was performed using ATRAN W6), and the results are shown in Table 1. As a comparative example, a laminated film consisting of a film only of a vapor-deposited film without coating and a film of only a water-soluble polymer and a film of only an aqueous ink, silica fine particles instead of metal alkoxide, or a mixture with a water-soluble resin using silica sol A laminated film made of a coating film was produced and similarly evaluated.

[0035]

[Table 1]

The vapor-deposited films coated with a coating agent (Nos. 1 to 5) have oxygen barrier properties and water vapor barrier properties, and have no coating properties. It was higher than that of No. 6 and showed a high gas barrier property. The water-soluble polymers (Nos. 7 and 8) and the water-based ink (No. 9) of Comparative Examples had slightly improved gas barrier properties, but a decrease in gas barrier properties was observed after storage under high humidity. Further, a mixed film of silica fine particles or a water-soluble resin using silica sol (No. 1)
Nos. 0 and 11) have no coating. Compared with No. 6, almost no improvement in gas barrier property was observed, which was inferior to the case of using the alkoxide of the gas barrier laminate film of the present invention, and clearly shows a difference due to the constitution.

Example 2 No. 1 of Example 1 1, No.
4, No. 6, No. The laminated film of No. 9 was bonded to an unstretched polypropylene (CPP, 30 μm) film with a polyol-isocyanate adhesive as the adhesive surface to obtain a gas barrier laminate. The oxygen permeability and water vapor permeability and the adhesive strength were measured and evaluated. Adhesive strength is measured at 15m
The measurement was performed under the conditions of m width, T-shaped peeling, and 300 mm / min.
The results are shown in Table 2. As a comparative example, a PET film having no vapor-deposited film was coated to a film thickness of 0.
The laminated film having a film of 3 μm formed thereon was also measured and evaluated in the same manner.

[0038]

[Table 2]

According to this, the coating film of the present invention is excellent in oxygen barrier property but low in water vapor barrier property even if the vapor deposition film as the first layer is not applied. By providing the vapor-deposited film on the base material, it was possible to obtain high oxygen barrier properties and water vapor barrier properties that cannot be obtained by a single substance. Also, the adhesive strength was significantly improved as compared with the film without the vapor deposition film.

[Embodiment 3] No. 2 of Embodiment 2. 13, N
o. 16, No. A laminated film obtained by laminating CPP on 18 was subjected to a predetermined elongation tensile test using a tensile tester, and then oxygen permeability and water vapor permeability were measured and flexibility was evaluated. The results are shown in Table 3.

[0041]

[Table 3]

A film having only a vapor-deposited film of the comparative example (No. 1)
In the case of 6), the film could not withstand deformation due to pulling due to elongation of several percent and cracked in the film, and the gas barrier property was significantly lowered.
The gas barrier laminate film (No. 13) of the present invention is 1
Almost no deterioration was observed up to about 0%, and the deterioration due to subsequent deformation due to tension was small, and it was considerably more flexible than the laminated film of the vapor deposition film of the comparative example. Further, the laminated film (No. 18) of the water-based gravure ink of the comparative example also starts to be deformed by pulling at an elongation of several%, and although some deterioration can be suppressed, its effect is slight.

Example 4 PET film (12 μm)
With Al ₂ O ₃ , SnO ₂ , Mg on one side
A thin film layer having a film thickness of 400 Å was formed by a vacuum evaporation method using an electron beam heating method using O as an evaporation source, and No. 1 of Example 1 was formed on the thin film layer. A coating film was formed in the same manner as in Example 1 using the coating agent of No. 4, and the oxygen permeability and water vapor permeability were measured and evaluated. As a comparative example, the one without coating was similarly measured and evaluated. The results are shown in Table 4.

[0044]

[Table 4]

From these results, Al ₂ O ₃ , SnO ₂ , M
Since the gas barrier property is remarkably improved by the coating using the coating agent formed on the vapor-deposited thin film layer made of gO, the effect of the coating of the gas barrier laminate film having the constitution of the present invention is clear.

Example 5 PET film (12 μm)
As a base material, in the same manner as in Examples 1 and 4, a thin film layer having a film thickness of 400 Å is formed on one surface of the same by vacuum evaporation using an electron beam heating method using SiO and Al ₂ O ₃ as evaporation sources.
No. 1 of Example 1 was formed on this thin film layer. A coating film was formed in the same manner as in Example 1 by using the coating agent of No. 4. Further, a CCP film (60 μm) was adhered with a polyol-isocyanate adhesive to prepare a laminated film, and a gas barrier laminated film was obtained. Using this laminated film, a pouch of 200 mm x 150 mm is prepared,
200 cc of water was enclosed as the content. This was subjected to a retort treatment (120 ° C.-20 min), and the oxygen permeability before and after the treatment was measured and the laminate strength was evaluated. As a comparative example, the one without coating was similarly measured and evaluated. The results are shown in Table 5.

[0047]

[Table 5]

From these results, the gas barrier laminate film of the present invention in which a coating film using a coating agent is formed on the vapor-deposited thin film layer suppresses the deterioration of the gas barrier property and the adhesion strength due to the retort treatment.

[0049]

As described above, the gas barrier laminate film of the present invention comprises a base material made of a polymer resin composition,
An aqueous solution containing a water-soluble polymer and at least one of (a) one or more metal alkoxides and a hydrolyzate thereof or (b) tin chloride, with a vapor deposition layer made of an inorganic compound as a first layer,
Alternatively, by coating a coating agent containing a water / alcohol mixed solution as a main component and heating and drying it as a second layer, a high gas barrier property is obtained, and flexibility and lamination strength are obtained. It has excellent water resistance, moisture resistance, and boiling / retort resistance, and its strength is sufficient for practical use even when laminated with other resins. That is, it enables long-term storage without impairing the gas barrier property even under a high temperature and high humidity atmosphere and without degrading the contents such as foods and pharmaceuticals. Further, the gas barrier property is not impaired even in post-processing such as printing, laminating and bag making as a packaging material.

[Brief description of drawings]

FIG. 1 is a schematic diagram illustrating the configuration of a gas barrier laminate film of the present invention.

[Explanation of symbols]

 1 Gas Barrier Laminated Film 2 Base Material 3 Inorganic Vapor Deposition Layer 4 Gas Barrier Coating Layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mika Gamo 1-5-1 Taito, Taito-ku, Tokyo Inside Toppan Printing Co., Ltd.

Claims (4)

[Claims] 1. A substrate comprising a polymer resin composition, a vapor deposition layer comprising an inorganic compound as a first layer, and a water-soluble polymer,
Gas barrier properties obtained by applying a coating agent containing (a) one or more metal alkoxides and / or a hydrolyzate thereof or (b) at least one of tin chloride or a water / alcohol mixed solution as a main component and heating and drying. A gas barrier laminate film, comprising a coating film laminated as a second layer. 2. The gas barrier laminate film according to claim 1, wherein the water-soluble polymer is polyvinyl alcohol. 3. The gas barrier laminate film according to claim 1, wherein the metal alkoxide is tetraethoxysilane, triisopropoxyaluminum, or a mixture thereof. 4. The gas barrier laminate film according to claim 1, wherein the vapor deposition layer made of the inorganic compound is any one of aluminum oxide, magnesium oxide, tin oxide and silicon oxide.