JP2000103001A - Laminated film having water vapor barrier characteristic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a transparent laminated film having water vapor barrier characteristics having a temperature dependence of water vapor transmittance same as that of an A1 deposited film. SOLUTION: A laminated film having water vapor barrier characteristics is provided with a base film 2 composed of a polymer resin composition, a metallic oxide deposited layer 3 composed of a metallic oxide, a coating film layer 4 and a sealant resin layer 5 composed of a heat-sealable thermoplastic resin. The coating film layer 4 is formed by applying a water solution containing a water-soluble polymer and one selected from (a) one or more alcoxide and/or its hydrolysate or (b) a tin chloride, or a coating agent containing a water/ alcohol mixed solution as a main agent. In a relation of water vapor transmission and temperature in a relative humidity of 90% of the laminated film having water vapor barrier characteristics, a value of a temperature dependence coefficient of water vapor transmittance is 1.08 or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Foods, pharmaceuticals, and the like are packaged and stored in packaging materials, but they are dried or absorbed by the humidity of the storage environment. In order to prevent the contents from being deteriorated due to such drying and moisture absorption, it is necessary to use a packaging material having a water vapor barrier property as the packaging material.

[0003] Therefore, conventionally, polyvinylidene chloride (hereinafter referred to as PVDC) film, PVDC coated film or aluminum (hereinafter referred to as Al) has been used.
A laminated film including a material having a high water vapor barrier property such as a vapor deposition film and an Al foil has been generally used as a packaging material.

[0004] However, PVDC containing chlorine is discarded after use, and there is a problem in the safety of gas generated when it is burned. In addition, packaging materials using Al foil are not suitable for disposal after use. It has the disadvantage that it is difficult to incinerate. In addition, since the amount of Al used is very small, there is no problem at the time of disposal of the Al-deposited film, but there is a problem that the appearance is difficult to distinguish from the Al foil. Therefore, in response to environmental problems, there is an increasing tendency to use these packaging materials as little as possible. Further, the packaging material using the Al foil or the Al vapor-deposited film has a disadvantage that the contents are opaque and the contents cannot be seen.

Therefore, in recent years, silicon oxide (SiO _x , silicon oxide) such as silicon monoxide (SiO), aluminum oxide (Al ₂ O ₃ ) has been used as a water vapor barrier material in place of PVDC, Al vapor-deposited film and Al foil. ), A thin film of a metal oxide such as magnesium oxide (MgO) formed on a polyethylene terephthalate (hereinafter referred to as PET) film by means of vapor deposition or the like. Packaging materials using oxide-deposited PET films) have begun to be generally used.

[0006]

However, the above-mentioned water vapor barrier packaging material using a metal oxide-deposited PET film has a higher vapor barrier property than a water vapor barrier packaging material using a PVDC or Al vapor-deposited film. Small dependence. That is, if the humidity is the same, the water vapor permeability of the packaging material is generally a linear relationship between the logarithmic value of the water vapor permeability and the temperature as shown in FIG. The inclination also becomes smaller. From the relationship shown in FIG. 1, the packaging material has a temperature of 40 ° C. and a relative humidity of 90% (hereinafter, 90%).
RH) and T ° C, 90% RH
The relationship of the water vapor transmission rate in the above is expressed by the following equation (1).
It is represented as Here, the packaging material using the metal oxide vapor-deposited PET film has a smaller water vapor permeability temperature dependency coefficient of Equation 1 than the packaging material using the PVDC or Al vapor-deposited film.

(Water vapor permeability at T ° C., 90% RH) = (water vapor permeability at 40 ° C., 90% RH) × (temperature dependence coefficient of water vapor permeability) 透過 (T−40) ‥‥ Equation 1 Water vapor permeability: g / m ² · day T: ° C. (arbitrary temperature) Temperature dependency coefficient: 1.062 or more (constant determined by packaging material)

Here, even when the humidity is the same, when the temperature changes, the saturated water vapor pressure also changes. The water vapor permeability of the packaging material is determined not by the humidity of the environment in which it is used but by the water vapor pressure of the environment. Therefore, if there is no packaging material that does not transmit water vapor at all, such as an Al foil, even if there is a packaging material having no temperature dependency of the water vapor transmission rate, the relationship as shown in FIG. 1 can be obtained. Then, the temperature dependency coefficient in Equation 1 is 1.062. In the case of an Al-deposited film, the value is 1.080 to 1.0.
090, PVDC is as large as 1.100 to 1.115, whereas metal oxide deposited PET film is 1.06
It is as small as 5 to 1.075.

[0009] The water vapor permeability of the packaging material is usually 40 ° C,
The value at 90% RH is used. Therefore, when the storage test of the contents is actually performed using the packaging material, 40
If the accelerated storage test is performed at a temperature of 90 ° C. to 90% RH, a storage result corresponding to the value of the water vapor permeability is obtained. However, at a lower temperature, for example, at room temperature or under refrigerated conditions, a packaging material having a high temperature dependency of water vapor permeability is 40 ° C., 90% RH.
Although the water vapor permeability is considerably lower than the water vapor permeability in
The difference from the water vapor permeability at 90 ° C. and 90% RH is smaller than that of a packaging material having a large temperature dependency. That is, since the packaging material using the metal oxide-deposited PET film has a small temperature dependency of the water vapor transmission rate, even at 40 ° C. and 90% RH, even if it has a better water vapor barrier property than other water vapor barrier packaging materials, it has room temperature. The water vapor barrier properties in the vicinity may be inferior to other water vapor barrier packaging materials. Therefore, the packaging material using the metal oxide vapor-deposited PET film can obtain a good result in the accelerated storage test at 40 ° C. and 90% RH, but the moisture-proof effect as expected when actually used. There is a problem that the anti-drying effect may not be exhibited.

Accordingly, the present invention provides a water vapor barrier packaging material using a film obtained by depositing a metal oxide on a base film made of a polymer resin composition (hereinafter referred to as a metal oxide deposited film). It is an object of the present invention to provide a water vapor barrier packaging material having a temperature dependency of water vapor transmission rate comparable to that of a vapor-deposited film.

[0011]

SUMMARY OF THE INVENTION The present invention is a laminated film having a water vapor barrier property using a metal oxide vapor-deposited film as a water vapor barrier material, and the temperature dependence coefficient of the formula 1 is 1.08 or more. It is a water vapor barrier laminated film.

In the first aspect of the present invention, a base film made of a polymer resin composition, a metal oxide deposited layer made of a metal oxide, a coating film layer, a sealant resin layer made of a heat-sealable thermoplastic resin Wherein the coating film layer comprises a water-soluble polymer and one of (a) one or more alkoxides and / or a hydrolyzate thereof, and (b) tin chloride. And a water / alcohol mixed solution as a main component, and formed by applying a coating agent, and the following relationship between the water vapor permeability and the temperature of the water vapor barrier laminate film at a relative humidity of 90% ( In the above formula (1), the value of the temperature dependency coefficient of the water vapor permeability is 1.08 or more; It is what it was. (Water vapor transmission rate at T ° C., 90% RH) = (water vapor transmission rate at 40 ° C., 90% RH) × (temperature dependence coefficient of water vapor transmission rate) ＾ (T−40) ‥‥ Formula 1 where water vapor transmission rate : G / m ² · day T: ° C. (arbitrary temperature) Temperature dependency coefficient: 1.062 or more (constant determined by packaging material)

[0013] In the second aspect of the present invention, the base film comprising the polymer resin composition is any one of a polyethylene terephthalate film, a stretched nylon film and a stretched polypropylene film. Film.

According to the third aspect of the present invention, the metal oxide forming the metal oxide deposited layer is made of one of silicon oxide, aluminum oxide and magnesium oxide. ,

Specifically, after forming a water vapor barrier coating film layer having a temperature dependent water vapor permeability on a metal oxide vapor deposition layer of a metal oxide vapor deposition film, at least heat sealing is possible. It is a water vapor barrier laminated film in which a thermoplastic resin (hereinafter referred to as a sealant resin) is laminated to form a sealant resin layer. This coating film layer can be formed by applying a coating agent described in Japanese Patent Application No. 6-234947 and drying by heating.

As the base film of the metal oxide vapor-deposited film, a polyethylene terephthalate (hereinafter referred to as PET) film, a stretched nylon (hereinafter referred to as ONy) film which is a base film of a general laminated film,
Alternatively, stretched polypropylene (hereinafter referred to as OPP) or the like can be used. A metal oxide such as silicon oxide, aluminum oxide or magnesium oxide is deposited on these base films, and the above-mentioned coating film layer is formed on the obtained metal oxide deposited layer. In addition, at the time of vapor deposition,
After performing an anchor coat treatment etc. on a base film, you may vapor-deposit.

[0017] A sealant resin, for example, low-density polyethylene, linear low-density polyethylene, unstretched polypropylene, ethylene-vinyl acetate copolymer is added to the metal oxide vapor-deposited film on which the coating film layer thus obtained is formed. By laminating such a resin to form a sealant resin layer, the water vapor barrier laminate film of the present invention can be obtained. Further, in order to improve various physical properties of the laminated film, a sealant resin layer may be laminated after laminating another film or resin on the metal oxide vapor-deposited film on which the coating film layer is formed.

Since the above-mentioned coating film layer itself has a water vapor barrier property, the water vapor barrier property of the metal oxide vapor-deposited film is further improved and does not decrease. In addition, the vapor barrier property of a metal oxide vapor-deposited film using a coating film layer or an ONy film as a base film is more temperature-dependent than that of a metal oxide vapor-deposited PET film. The temperature dependence of the water vapor transmission rate also increases in the water-soluble laminated film, and the coefficient indicating the temperature dependence of the water vapor transmission rate of Equation 1 is 1.
08 or more, and at least the temperature dependency of the water vapor permeability comparable to that of an Al vapor-deposited film can be obtained.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a schematic view for explaining the structure of one embodiment of the laminated film 1 of the present invention.

In FIG. 2, reference numeral 1 denotes a water vapor barrier laminate film, 2 denotes a base film, 3 denotes a metal oxide deposited layer, 4 denotes a coating layer, and 5 denotes a sealant resin layer. .

The base film 2 is in the form of a sheet or a film, and may be any of those used as a base material of ordinary laminated films, such as PET, ONy, and OPP. The base film 2 is appropriately selected from the above materials depending on the application. Known additives such as an antistatic agent, an ultraviolet absorber, a plasticizer, a lubricant, and a coloring agent may be added to the base film 2 as necessary. Further, the surface of the base film 2 may be subjected to a surface treatment such as a corona treatment, an ozone treatment, and an anchor coat treatment to improve the adhesion of the metal oxide vapor deposition layer.

The metal oxide deposited layer 3 is made of a simple substance of an oxide such as silicon, aluminum or magnesium, or a composite thereof, and is formed by a vacuum deposition method, a sputtering method, a plasma vapor deposition method (CVD method) or the like. Formed by the process. In particular, aluminum oxide is colorless and transparent and can be used for a wide range of applications. The thickness of the metal oxide vapor-deposited layer 3 varies depending on the application and the like. However, if the thickness is 50 ° or less, there is a problem in the continuity of the vapor-deposited layer. Is 50 to 3000 °.

The coating film layer 4 is formed of an aqueous solution containing a water-soluble polymer and (a) at least one of an alkoxide of at least one metal or the like and / or a hydrolyzate thereof and (b) tin chloride, or water / alcohol. It consists of a coating agent whose main component is a mixed solution. A solution in which a water-soluble polymer and tin chloride are dissolved in an aqueous (water or water / alcohol mixture) solvent, or a solution in which an alkoxide such as a metal is directly or preliminarily hydrolyzed or mixed. Is applied to the metal oxide vapor-deposited layer 3 on the base film 2 and dried by heating. Each component contained in the coating agent will be described in detail below.

Examples of the water-soluble polymer used for the coating agent include polyvinyl alcohol, starch, methylcellulose, sodium alginate, etc., and polyvinyl alcohol (hereinafter, referred to as PVA) is most excellent in terms of barrier properties.

Further, tin chloride is stannous chloride, stannic chloride,
Alternatively, a mixture thereof may be used, and an anhydride or a hydrate may be used.

Further, the alkoxide has the general formula: M (OR) _n (M: metal such as Si, Al, Ti, etc., R: CH ₃ , C ₂ H
Alkoxides such as metals which can be represented by an alkyl group (e.g., ₅ ), among which tetraethoxysilane and triisopropoxyaluminum are preferred 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 of several components. Further, as long as the barrier properties of the coating agent are not impaired, known additives such as dispersants, stabilizers and coloring agents can be used. Agents may be added.

As a method for applying the coating agent, known means such as a dipping method, a roll coating method, a screen printing method, and a spray method which are usually used are used. The thickness of the coating film layer varies depending on the type of the coating agent, but is 0.01 to 100 after drying.
It is sufficient if the thickness is in the range of 50 μm or more.
It is desirable that the thickness be 1 to 50 μm.

For the sealant resin layer 5, a resin having a heat sealing property such as low-density polyethylene, linear low-density polyethylene, unstretched polypropylene, and ethylene-vinyl acetate copolymer can be used. This sealant resin layer 5
May be provided by laminating a film-formed material via an adhesive, or laminating a molten resin by direct extrusion coating. The sealant resin used may be properly used depending on the application.

Further, in the water vapor barrier laminate film of the present invention, if necessary, a plurality of resins may be laminated via an adhesive layer or a printed layer may be provided.

The present invention provides a water vapor barrier material by forming a water vapor barrier coating film layer having a temperature dependence on water vapor permeability on a metal oxide vapor deposition layer of a metal oxide vapor deposition film. While using the oxide-deposited film, the temperature dependence coefficient of Equation 1 is 1.08
A water vapor barrier laminate film as described above is obtained.

[0032]

<Example 1> A metal oxide vapor-deposited layer having a thickness of 400 ° was formed on a 12-μm-thick PET film by vacuum vapor deposition using an electron beam heating method with silicon oxide (SiO) as a vapor deposition source. A coating agent obtained by combining the following compositions and mixing them in a predetermined ratio is applied by a coater, and dried in an oven at 120 ° C. for 1 minute, and a film thickness of about 0.3 μm
Was formed. The uncoated polypropylene film (30
μm) to form a sealant resin layer, thereby obtaining a water vapor barrier laminate film.

(Components of Coating Agent) (A) 3.0 wt% water / isopropyl alcohol solution of polyvinyl alcohol (water: isopropyl alcohol weight ratio 90:10) (B) 0.1N hydrochloric acid 89 in 10.4 g of tetraethoxysilane Then, a hydrolyzed solution having a solid content of 3% by weight (in terms of SiO) hydrolyzed was added thereto and stirred for 30 minutes. (C) 6.0 g of triisopropoxy aluminum was added to 80
A hydrolyzed solution having a solid content of 3 wt% (in terms of Al ₂ O ₃ ) obtained by dissolving in 90 g of hot water at 90 ° C., adding 4 g of 5N hydrochloric acid and peptizing. (D) 3 wt% water / ethanol solution of stannous chloride (anhydride) (water: ethanol weight ratio 50:50)

(Composition of Coating Agent) No. 1 (A) / (B) Compounding ratio (wt%) 40/60 No. 2 (A) / (B) / (C) Compounding ratio (wt%) 40/50/10 No. 3 (A) / (D) Compounding ratio (wt%) 40/60 4 (A) / (B) / (D) Compounding ratio (wt%) 30/40/30 5 without coating

Using the obtained four types of water vapor barrier laminate films (Nos. 1 to 4) and the comparative water vapor barrier laminate film (No. 5), each was 10 cm ×
After making a 10 cm bag, the bag is filled with about 30 g of calcium chloride, sealed, stored at 20 ° C., 30 ° C., and 40 ° C. under 90% RH conditions, and its weight change is measured over time. The water vapor permeability under each storage condition was determined. The temperature dependency coefficient in Equation 1 was calculated from the obtained water vapor permeability at each temperature.

The film of the comparative example (No. 5)
Water vapor permeability at 90 ° C. and 90% RH is 0.99 g / m
² · day and the temperature dependence coefficient was 1.073, whereas the films (Nos.
Water vapor permeability at 0 ° C. and 90% RH is 0.23 to
The barrier property is high at 0.29 g / m ² · day, and the temperature dependence coefficient is in the range of 1.081 to 1.085.
The temperature dependence of the water vapor permeability increased.

Example 2 A metal oxide vapor-deposited layer having a thickness of 400 ° was formed on a 12 μm-thick PET film by vacuum vapor deposition using an electron beam heating method, using aluminum oxide and magnesium oxide as vapor deposition sources. No. 1 of Example 1 was placed on this metal oxide deposited layer. Using the coating agent No. 4, a coating was formed in the same manner as in Example 1. A low-density polyethylene film (60 μm) was laminated on the coated surfaces of these films in the same manner as in Example 1 to obtain a water vapor barrier laminated film. As a comparative example, a water vapor barrier laminate film having no coating film layer was produced.

Using these films, the temperature dependence coefficient of the water vapor permeability was determined in the same manner as in Example 1.
The water vapor permeability at 40 ° C. and 90% RH was 1.24 for the laminated film using aluminum oxide and magnesium oxide as the evaporation source in the film of the comparative example,
1.48g / m ² · day in which it was, but each is a laminated film of Example 0.37,0.43g / m ² · da
y. The temperature dependence coefficients were 1.070 and 1.072 in the comparative example, respectively, whereas the temperature dependence increased to 1.096 and 1.091 in the example, respectively.

Example 3 ONy film (15 μm)
A metal oxide vapor-deposited layer having a thickness of 400 ° was formed by vacuum vapor deposition using an electron beam heating method with silicon oxide as a vapor deposition source, and an OPP film (2
0 μm) on a deposition surface of a low-density polyethylene film (6
0 μm) to obtain a water vapor barrier laminated film.

Using this film, the temperature dependency coefficient of the water vapor transmission rate was determined in the same manner as in Example 1. 40
The water vapor permeability at 90 ° C. and 90% RH is 1.17 g /
m ² · day, and the temperature dependency coefficient was as high as 1.089.

Example 4 OPP film (20 μm)
A metal oxide vapor-deposited layer having a thickness of 400 ° was formed by a vacuum vapor deposition method using an electron beam heating method, using silicon oxide as a vapor deposition source.
Using the coating agent of No. 4, a coating film layer was formed in the same manner as in Example 1. An unstretched polypropylene film (25 μm) was laminated on the coated surface of the film to obtain a water vapor barrier laminated film.

Using this film, the temperature dependency coefficient of the water vapor transmission rate was determined in the same manner as in Example 1. 40
The water vapor permeability at 90 ° C. and 90% RH is 0.54 g /
m ² · day, and the temperature dependency coefficient was as high as 1.083.

[0043]

As described above, the water vapor barrier laminate film of the present invention has a higher water vapor permeability than the conventional laminated film having a vapor barrier layer of a PET film on which a metal oxide is deposited. It is a water vapor barrier laminate film that has a large dependence and has substantially no difference between the temperature dependence and the temperature dependence of the water vapor transmission rate of the aluminum vapor-deposited film. Therefore, by comparing the water vapor permeability at 40 ° C. and 90% RH with another water vapor barrier packaging material (for example, an aluminum vapor-deposited film), the content storage performance of the film in an actual use environment can be compared. That is, unlike a laminated film using a conventional metal oxide vapor-deposited PET film, even if good results are obtained in the accelerated storage test at 40 ° C. and 90% RH, the temperature dependence of the water vapor permeability is small. However, when used in practice, the problem that the anti-moisture effect and anti-drying effect as expected may not be exhibited is solved.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of a relationship between a water vapor permeability and a temperature of a packaging material at the same humidity.

FIG. 2 is a schematic diagram illustrating the configuration of an embodiment of the water vapor barrier laminate film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Water vapor barrier laminated film 2 ... Base film 3 ... Metal oxide vapor deposition layer 4 ... Coating coating layer 5 ... Sealant resin layer

Continued on the front page F-term (reference) 4F100 AA05C AA05H AA17B AA18B AA19B AA20B AH02B AH02H AH08B AH08H AK01A AK01C AK01D AK07A AK42A AK48A AK51G BA04 BA07 BA10A BA10D BA13B00 JBJBJJBJBBJDJ

Claims (3)

[Claims] 1. A base film comprising a polymer resin composition,
A metal oxide vapor-deposited layer made of a metal oxide, a coating film layer, a water vapor barrier laminated film including a sealant resin layer made of a heat-sealable thermoplastic resin, wherein the coating film layer is made of a water-soluble polymer and ,
An aqueous solution comprising (a) one or more alkoxides and / or hydrolysates thereof or (b) any one of tin chloride;
Alternatively, it is formed by applying a coating agent containing a water / alcohol mixed solution as a main component, and in the following relationship (Equation 1) between the water vapor permeability and the temperature of the water vapor barrier laminate film at a relative humidity of 90%: A water vapor barrier laminate film having a temperature dependence coefficient of water vapor permeability of 1.08 or more. (Water vapor transmission rate at T ° C., 90% RH) = (water vapor transmission rate at 40 ° C., 90% RH) × (temperature dependence coefficient of water vapor transmission rate) ＾ (T−40) ‥‥ Formula 1 where water vapor transmission rate : G / m ² · day T: ° C. (arbitrary temperature) Temperature dependency coefficient: 1.062 or more (constant determined by packaging material) 2. The steam barrier laminate film according to claim 1, wherein the substrate film comprising the polymer resin composition is any one of a polyethylene terephthalate film, a stretched nylon film and a stretched polypropylene film. 3. The steam barrier laminate film according to claim 1, wherein the metal oxide forming the metal oxide vapor-deposited layer comprises one of silicon oxide, aluminum oxide and magnesium oxide.