JP2003071969A - Transparent gas barrier film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transparent gas barrier film comprising an aluminum oxide vapor-deposited film reduced in charge and excellent in processability such as printing, lamination or the like. SOLUTION: The transparent gas barrier film is constituted by successively forming an aluminum oxide layer and an overcoat layer of which the surface resistance value is below 1×10<13> Ω/(square) on at least the single surface of a plastic film substrate and characterized in that the coefficient of stationary friction of the surface on the side opposite to one surface of the film is not more than 0.5 and the coefficient of dynamic friction is not more than 0.4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transparent gas barrier film suitable for packaging, which has excellent gas barrier properties against oxygen and water vapor and excellent post-processability such as printing and laminating.

[0002]

2. Description of the Related Art Among various functions conventionally required for packaging materials for foods, industrial materials, and pharmaceuticals, oxygen and water vapor barrier properties, so-called gas barrier properties, are one of the important properties from the viewpoint of maintaining the quality of contents. Therefore, aluminum foil, aluminum vapor deposition film, vinylidene chloride coating film, silicon oxide vapor deposition film, aluminum oxide vapor deposition film and the like have been used as materials having excellent gas barrier properties. However, in response to recent environmental problems and the Product Liability Law, transparent vapor deposition that forms metal oxides such as silicon oxide and aluminum oxide that can confirm and visually check the contents and does not generate harmful gases such as chlorine during combustion. Film has come into the spotlight as a new material. Among them, the aluminum oxide vapor deposition film, which is advantageous in terms of productivity and cost, is drawing attention.

However, since this aluminum oxide vapor-deposited film is composed of a plastic film and aluminum oxide, which is an electric non-conductor, it is easily charged when it is unwound from the film roll or when it comes into contact with a rubber roll, and the static electricity is dissipated. It has a problem that it is difficult to do. In particular, thickness 1 often used for packaging materials
Films using polyethylene terephthalate with a thickness of 2 μm or less are markedly peeled and electrified, causing film running defects such as wrinkles due to reduced slipperiness due to electrification, and printing defects due to ink repellency that cause problems due to film electrification. I often do it. This property is mitigated by adding a lubricant such as an inorganic filler or an antistatic agent to the plastic film, but the antistatic agent bleeding on the film surface impairs the film forming property or adhesion of the vapor deposition layer. However, when the amount of the filler added is large, there is also a problem that the haze of the film increases and the transparency is impaired. Therefore, the addition to the film is limited.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide an aluminum oxide vapor-deposited film which reduces the electrification of the film and is excellent in processability such as printing and laminating.

[0005]

In the present invention, the above object is achieved by the following method. [1] On at least one side of the plastic film substrate,
Aluminum oxide layer and surface resistance value is 1 × 10 ¹³ Ω / □
And a coefficient of static friction between one surface of the film and a surface on the opposite side of the film is 0.5 or less, and a coefficient of dynamic friction is 0.4 or less. A transparent gas barrier film. [2] Kanakin No. 3 cotton cloth whose overcoat layer is made of polyester resin and an additive having electrical conductivity, and which is wet with ethyl acetate using a friction tester type II (load 200 g) according to JIS L0823. Face 5
Oxygen transmission rate after rubbing (unit cm ³ / m ² · 24h
-Atm) and water vapor transmission rate (g / m ² · 24h) are both 3 or less, the transparent gas barrier film according to the above [1]. [3] The total light transmittance of the plastic film substrate is 10
The transparent gas barrier film according to the above [1] or [2], which is 98% or more and has a haze of 7% or less when 0%.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The transparent gas barrier film of the present invention comprises:
Aluminum oxide layer and surface resistance value is 1 × 10 ¹³ Ω / □
It has a basic structure in which overcoat layers of less than 1 are sequentially formed.

In the present invention, the material of the plastic film substrate is not particularly limited, but as a typical example,
Polyester (polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, etc.), polyolefin (polyethylene, polypropylene, etc.), polyamide (nylon 6, nylon 66, etc.), polycarbonate, polyimide, polyvinyl chloride, etc.,
Examples thereof include films made of copolymers of these polymers and other organic substances. These plastic film base materials include known additives such as antistatic agents within a range that does not impair vapor deposition suitability due to bleeding on the surface.
Antioxidants, lubricants, anti-coloring agents, ultraviolet absorbers, plasticizers, coloring agents and the like may be added. These plastic film substrates may be unstretched films, uniaxially stretched films or biaxially stretched films, but biaxially stretched films are preferable from the viewpoint of dimensional stability, mechanical properties and gas barrier stability. Further, the plastic film substrate may be subjected to surface treatment such as corona discharge treatment, flame treatment, plasma treatment, glow discharge treatment or the like, or known anchor treatment prior to the formation of the vapor deposition layer. The thickness of these plastic film base materials is not particularly limited, but is 6 to 10 in consideration of machinability such as vapor deposition processing.
About 0 μm is preferable.

In order to form the aluminum oxide layer on at least one surface of the plastic film substrate, known methods such as heating vapor deposition, sputtering, ion plating method can be applied. The thickness of the aluminum oxide layer can be arbitrarily set according to the required characteristics,
The range of 5 nm to 200 nm is desirable. If the thickness is less than 5 nm, the gas barrier property may be insufficient, and
If the thickness exceeds 200 nm, the internal strain increases, which may cause cracks or curl of the film.

The Au formed on the aluminum oxide layer
The bar coat layer is formed along with the running of the plastic film substrate.
In order to dissipate static electricity efficiently, the surface resistance value is 1 ×
10 ¹³Must have electrical conductivity of less than Ω / □
It

The material of the overcoat layer is not particularly limited, but it is preferable to use an organic resin from the viewpoints of the protective effect on the aluminum oxide layer and the adhesiveness for printing and laminating. A polyester resin containing, as an additive, a substance exhibiting electrical conductivity due to an oxide, a conductive polymer or the like) or ion conductivity (ionic surfactant or the like) is preferable. The lower limit of the surface resistance value is not particularly defined, but in the method of imparting electrical conductivity with an additive, it is preferable to minimize the amount of the additive from the viewpoint of performance such as adhesion and economical efficiency. In this case, the lower limit of the surface resistance value is set to about 1 × 10 ⁷ Ω / □.

The thickness of the overcoat layer is usually 0.01 to 3 μm.

In the present invention, in order to prevent the occurrence of wrinkles when the film is wound, the static friction coefficient between one surface of the film and the opposite surface is 0.5 or less, and the dynamic friction coefficient is 0.4.
It must be: The lower limit of the friction coefficient is zero by definition, but it is more preferable that both the static friction coefficient and the dynamic friction coefficient are 0.2 or more in order to avoid winding deviation in a roll state due to slipperiness of the film.

In the present invention, in order to maintain the gas barrier property after printing and laminating, it is preferable that the overcoat layer has appropriate solvent resistance. The solvent resistance can be evaluated by measuring the gas barrier property after rubbing the overcoat surface with a cotton cloth impregnated with an organic solvent,
In the present invention, a friction tester according to JIS L0823
Oxygen permeability (unit cm ³ / m ² · 24h · atm) and water vapor permeability (Kanakin No. 3 cotton cloth moistened with ethyl acetate using Type II (load 200 g) after rubbing the overcoat surface 5 times Both g / m ² · 24h) are preferably 3 or less.

The transparent gas barrier film of the present invention is mainly used as a transparent packaging material. Examples of its use include dry foods (confectionery, snacks, etc.), aquatic foods (side dishes, etc.) and non-food products (disposable body warmers, electronic devices). Examples of the packaging material include parts.
For this purpose, high transparency is required for the visibility of the contents and the appearance of the print. Therefore, in the present invention, the total light transmittance is 1
When set to 00%, it is 98% or more and the haze is 7%.
The following is preferable.

[0015]

EXAMPLES The present invention will be described below with reference to examples. In addition,
Each characteristic value in the examples is measured by the following measuring methods.

(1) Surface resistance value It was measured under the conditions of 23 ° C. and 65% RH using a Mitsubishi Chemical Hiresta (measurable up to 1 × 10 ¹³ Ω / □).

(2) Oxygen permeability (cm ³ / m ² · 24h
-Atm) It measured on the conditions of 20 degreeC and 0% RH using the oxygen transmission meter OX-TRAN SM by MOCON.

(3) Water vapor transmission rate (g / m2 · 24h) MOCON water vapor transmission rate meter PERMTRAN TW
The measurement was performed using IN under the conditions of 40 ° C. and 90% RH.

(4) Coefficient of static friction and coefficient of dynamic friction 23 ° C at 6 ° C with in-house manufactured equipment according to ASTM D1894
It was measured under the condition of 5% RH.

(5) On top of the gas barrier overcoat layer (aluminum oxide layer in Comparative Example 1) after printing, printing ink (Lamic F2 manufactured by Dainichiseika Co., Ltd.)
20 white / trade name) was printed with a bar coater to a thickness of 1 μm. Then, the transmittances of oxygen gas and water vapor were measured by the methods (2) and (3).

(6) Suitability for running a film Using a general rewinding machine, a film of 1000 mm
A tension of 130 N was applied to the width, and rewinding was performed at a speed of 200 m / min to check whether a running abnormality such as wrinkling occurred.

(7) Total light transmittance and haze Light transmittance meter NDH-1001DP manufactured by Nippon Denshoku Industries Co., Ltd.
The total light transmittance and the haze of the film were measured using (the light transmittance and the total light reflectance measuring method A of JIS K7105 (Plastic optical property test method)).

(Example 1) (1) Biaxially stretched polyethylene terephthalate film (thickness
Of aluminum and oxygen gas on the surface of
Form a 20 nm thick aluminum oxide layer by vapor deposition
Made, oxygen permeability 2.0 cm³/ M^Two・ 24h ・ at
m, water vapor transmission rate 2.0 g / m^Two.Oxide showing 24h
A luminium vapor deposition film was obtained. (2) On the other hand, polyester resin (Vylon 20 manufactured by Toyobo Co., Ltd.
S / trade name) toluene: methyl ethyl ketone: acetic acid
Dilute the solvent with chill = 1: 1: 1 so that the solid content becomes 6%.
Then, add this solution to an antistatic agent Statiside concentrate (rice
Oxidation of (1) by adding 0.3% in weight ratio
0.2 μm thick conductivity applied on aluminum layer
An overcoat layer was formed. Surface of overcoat surface
Resistance value is 3 × 10^TenIt was Ω / □. Also, load 20
0g Gakushin-type friction tester (JISL0823 friction tester
Kankin 3 wetted with ethyl acetate (based on Type II)
Oxygen permeation after rubbing the overcoat surface 5 times with No. cotton cloth
The rate is 4.5 cm³/ M ^Two・ 24h ・ atm, water
Vapor transmission rate is 3.5g / m^Two・ It was 24 hours. The result
It shows in Table 1. (Example 2) Polyester resin (Byron 2 manufactured by Toyobo Co., Ltd.)
Isocyanate-based curing agent (Toyo Mort)
CAT-10 / product name) manufactured by the company
By the way, toluene: methyl ethyl ketone: ethyl acetate =
Dilute to a solid content of 6% with a 1: 1: 1 solvent,
Antistatic agent Statiside concentrate is added to this solution in a weight ratio.
Aluminum oxide steam of (1) of Example 1 with addition of 0.2%
It is applied to the adhesive film and has a thickness of 0.2 μm
A coat layer was formed. The surface resistance of the overcoat surface is
4 x 10¹¹It was Ω / □. In addition, academic load with a load of 200g
Type friction tester (corresponding to JIS L0823 friction tester type II
Kanakin No. 3 cotton cloth moistened with ethyl acetate using
The oxygen transmission rate after rubbing the overcoat surface 5 times is 2.
7 cm³/ M^Two・ 24h ・ atm, water vapor transmission rate
Is 2.3 g / m^Two・ It was 24 hours. The results are shown in Table 1.
You

(Comparative Example 1) The overcoat layer was not formed, and the aluminum oxide vapor-deposited film of (1) of Example 1 was used as it was. The surface resistance of the aluminum oxide vapor deposition surface exceeded 1 × 10 ¹³ Ω / □ and could not be measured. In addition, Gakushin-type friction tester with a load of 200 g (JIS
Oxygen permeability after rubbing the aluminum oxide vapor-deposited surface 5 times with a Kanakin No. 3 cotton cloth wet with ethyl acetate using a L0823 friction tester type II) is 50 cm ³ / m ² · 2.
4h · atm, water vapor transmission rate is 20g / m ² · 2
It was 4 h. The results are shown in Table 1.

(Comparative Example 2) The procedure of Example 1 was repeated, except that the antistatic agent was not added to the polyester resin solution. The surface resistance of the overcoat surface is 1 × 10 ¹³
Ω / □ was exceeded and measurement was not possible. Also, load 20
Oxygen permeability after rubbing the overcoat surface 5 times with Kanakin No. 3 cotton cloth wet with ethyl acetate using 0 g of Gakushin type friction tester (based on JIS L0823 friction tester type II) is 4.5 cm. ^{It was 3} / m ² · 24h · atm and the water vapor permeability was 3.5g / m ² · 24h. The results are shown in Table 1.

[0026]

[Table 1]

In Table 1, in Examples 1 and 2 in which the surface resistance value and the friction coefficient are within the range of the present invention, the film can be wound well without wrinkles or the like during film running. Further, in Example 2, since the solvent resistance of the overcoat layer was excellent, the gas barrier property did not deteriorate due to the rubbing of the vapor deposition surface even after printing.

On the other hand, in Comparative Example 1, static electricity was less likely to be dissipated, so that sticking due to electrification of the unwound film was remarkable, and since the coefficient of friction was also large, wrinkles were remarkable at the winding portion. In addition, since there is no coat layer for protecting the vapor deposition layer, the gas barrier property after printing is greatly deteriorated due to scratching of the vapor deposition surface. Further, in Comparative Example 2, the coefficient of friction is within the range of the present invention, but the surface resistance value is outside the range of the present invention, and static electricity is difficult to dissipate.
Similarly, stickiness due to electrification was large and wrinkles were unavoidable.

[0029]

As described above, when the transparent gas barrier film of the present invention is used as a packaging film, it prevents wrinkles and the like from occurring in the printing and laminating steps, and also has a gas barrier property by the same processing. It exhibits excellent processability with little deterioration.

Continued front page    (72) Inventor Masayoshi Teranishi             Toyo Metalai, 33 Nagabushi, Mishima City, Shizuoka Prefecture             Jing Co., Ltd. Mishima Factory F-term (reference) 4F006 AA12 AA17 AA35 AA36 AA38                       AA39 AB74 BA05 DA01 EA02                 4F100 AA19B AA19D AK01A AK41C                       AK41E AK42 AT00A BA03                       BA05 BA06 BA07 BA10A                       BA10C BA10E CA23C CA23E                       CC00C CC00E EH46 EH66                       EJ38 EJ65C EJ65E GB15                       GB23 JD02 JD03 JD04 JG04C                       JG04E JJ01C JJ01E JK16                       JL01 JN01 JN08 YY00 YY00C                       YY00E

Claims (3)

[Claims] 1. An aluminum oxide layer and a surface resistance value of 1 × 10 5 on at least one surface of a plastic film substrate.
^It has a structure in which overcoat layers of less than ¹³ Ω / □ are sequentially formed, and the static friction coefficient between one surface of this film and the opposite surface is 0.5 or less, and the dynamic friction coefficient is 0.4 or less. A transparent gas barrier film characterized by being present. 2. The overcoat layer comprises a polyester resin and an additive exhibiting electrical conductivity, and JIS L0
Oxygen permeability (unit: cm ³ / m ² ) after rubbing the overcoat surface 5 times with a Kanakin No. 3 cotton cloth wet with ethyl acetate using a friction tester type II by 823 (load 200 g)
・ 24h ・ atm) and water vapor transmission rate (g / m ²・ 24)
The transparent gas barrier film according to claim 1, wherein both of h) are 3 or less. 3. The total light transmittance is 98% or more and the haze is 7% or less when the plastic film substrate is taken as 100%.
The transparent gas barrier film described.