JP3214587B2 - Gas barrier film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention has excellent gas barrier properties,
Excellent as a packaging material that requires airtightness for foods, pharmaceuticals, electronic parts, etc., or a gas barrier material such as a moisture-proof film for EL, which has good overall characteristics that balances two characteristics such as heat treatment and flexibility. It relates to a film having characteristics.

[0002]

2. Description of the Related Art Films having excellent gas barrier properties include those obtained by laminating an aluminum foil or a vapor-deposited film on a plastic film, and those coated with vinylidene chloride or ethylene vinyl alcohol copolymer. Further, as a device using an inorganic thin film, a device in which a silicon oxide, an aluminum oxide thin film, or the like is laminated is known.

[0003]

However, such a conventional gas barrier film has the following problems. Aluminum foil and aluminum vapor-deposited film laminates are economical and have excellent gas barrier properties, but they are opaque, so the contents are not visible during packaging, and they do not transmit microwaves, so microwave ovens cannot be used. There are inconveniences such as. Those coated with vinylidene chloride or ethylene vinyl alcohol copolymer do not have sufficient gas barrier properties against water vapor, oxygen, etc., and the decrease is remarkable especially at high temperature treatment. In addition, with respect to vinylidene chloride, there is generation of chlorine gas at the time of incineration, and there is also a concern about the influence on the global environment. On the other hand, as a gas barrier film in which the contents can be seen and a microwave oven can be used, Japanese Patent Publication No. 51-48511 proposes a gas barrier film in which Six Oy (for example, SiO ₂ ) is deposited on the surface of a synthetic resin body. SiOx system with good gas barrier properties (x = 1.3-1.8)
Has a slightly brown color and is insufficient as a transparent gas barrier film.

There is a colorless and transparent example mainly composed of aluminum oxide (Japanese Patent Application Laid-Open No. 62-101428), but there is a problem that the oxygen barrier property is insufficient and the mechanical properties are not so high. In addition, in order to obtain a retort properties, Al ₂ O ₃ proposal of the gas barrier film using a thin film and a SiOx film by laminating are also (JP-2-1
94944), however, the film forming process becomes complicated and cannot be said to be a practical method. In addition, these gas barrier films
Attention must be paid to the handling, and it is still a problem that the gas barrier property is greatly deteriorated depending on the post-process such as lamination or printing or the handling before the lamination. Thus, it has both sufficient oxygen barrier properties and water vapor barrier properties, and
At present, there is no method for practically producing a colorless and transparent gas barrier film with little deterioration of barrier properties against mechanical deformation due to a post-process or handling.

[0005]

SUMMARY OF THE INVENTION The present invention does not provide a gas barrier film having sufficient gas barrier properties, and having good overall properties in which two properties such as flexibility and heat treatment, including printability, are compatible. It is assumed that. That is, in a gas barrier film in which a thin film of a compound or a mixture of two or more elements or oxides thereof is formed on at least one surface of a plastic film substrate, any one of the unit composition elements in the thin film is used. A gas barrier film characterized in that the concentration changes by 10% or more in the thickness direction with respect to the average concentration of the constituent elements, and the cycle of the change is two times or more. A gas barrier film according to claim 1 provided with a gas barrier layer, and a packaging or gas barrier film using the gas barrier film according to claim 1 or 2.

The plastic substrate referred to in the present invention is a film obtained by melt-extruding an organic polymer and stretching, cooling, and heat setting in the longitudinal direction and / or the width direction as necessary. Organic polymers include polyethylene, polypropylene, polyethylene terephthalate, polyethylene-2,6-naphthalate, nylon 6, nylon 4,
Nylon 66, nylon 12, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, wholly aromatic polyamide, polyamide imide, polyimide, polyether imide, polysulfone, polyphenylene sulfide, polyphenylene oxide and the like. These (organic polymer) organic polymers may be copolymerized or blended in small amounts with other organic polymers.

Further, known additives such as an ultraviolet absorber, an antistatic agent, a plasticizer, a lubricant, and a coloring agent may be added to the organic polymer, and the transparency thereof is not particularly limited. However, when used as a transparent gas barrier film, those having a transmittance of 50% or more are preferred. The plastic film of the present invention may be subjected to corona discharge treatment, glow discharge treatment, or other surface roughening treatment prior to laminating the thin film layer, as long as the object of the present invention is not impaired. ,Also,
Known anchor coat treatment, printing, and decoration may be applied. The thickness of the plastic film of the present invention is preferably in the range of 5 to 500 μm, more preferably 8 to 300 μm. The product of the present invention may be used as it is, or may be used by laminating or coating another organic polymer film or a thin layer.

In the present invention, two or more elements or
There is no particular limitation on the compound or mixture thin film made of the oxide as long as it is a thin film having gas barrier properties.
Compounds or mixtures of semiconductors, oxides, nitrides and the like may be used. That is, non-metallic elements (B, C, Si,
P, S, Ge, As, Se, etc.), metal elements (Na, M
g, Al, K, Ca, Sc, Ti, V, Sb, Cr, M
n, Fe, Co, Ni, Cu, Zn, Ga, Y, Zr,
Nb, Mo, Ag, Cd, In, Sn, Ta, W, A
u, Pb, etc.) and rare earth elements (Nd, Sm, Gd, Tb)
Etc.) are not particularly limited as long as they have gas barrier properties, such as alloys, compounds, and mixtures of two or more metals .

For example, compounds include Al 2 O 3, B
2 O3, BaO, Bi2 O3, CaO, CeO2, Cr
2 O3, Fe3 O4, In2 O3, MgO, MnO, M
oO3, Na2O, Nd2O3, NiO, PbO, Sb
2 O3, SiO, SiO2, TiO2, Tl2 O3, V
2 O5, WO3, ZnO2 and other oxides
Compounds , MnS, PbS, SnS, ZnS, CdS
e, InSe, SbSe, SiTe, sulfide such as SnTe, telluride, selenide, AgCl, CoCl2,
CrCl2, FeCl2, KCl, NaCl, AlF3
, CaF2, CeF3, CsF, NaF, CoBr2
, CsBr, MgBr, NiBr, NaI, KI, C
and halides such as uI. Among them, particularly preferred as the gas barrier thin film are compounds, composites, and the like composed of two or more simple substances such as aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, zirconium oxide, titanium oxide, boron oxide, and indium oxide. It is a mixture thereof, and the film thickness is not limited as long as it is a thickness used as a gas barrier thin film, but is preferably 20,000 ° (angstrom) or less from the viewpoint of flexibility and 30 ° or more from the viewpoint of gas barrier properties. More preferably 50 to 10,000 °, still more preferably 70 to
8000.

As a method for producing the gas barrier thin film of the present invention, a PVD method (physical vapor deposition method) such as a vacuum vapor deposition method, a sputtering method, an ion plating method, or a CVD method (chemical vapor deposition method) is appropriately used. For example, in the case of a vacuum evaporation method, there is an example in which a beam heating evaporation method is used. The beam heating evaporation method is a vacuum evaporation method using at least one beam source as a heating means, and the beam heating is to use a high energy density beam as a heating source. And various ion beams, laser beams and the like are known. The number of beam sources is at least one. That is, a single beam or a plurality of beams may be used, or a beam may be used in combination with another heating method. As the other heating method referred to here, resistance heating, high-frequency induction heating, and common use with other beam heating can be considered, but it is not particularly limited to these. Alternatively, a reactive vapor deposition method in which oxygen, nitrogen, water vapor, or the like is introduced as a reactive gas, or ozone, ion assist, or the like is used may be used. Further, the deposition conditions may be changed such as applying a bias or the like to the substrate, or increasing or cooling the substrate temperature.

As another method, there is a method in which a sputtering voltage is changed in a sputtering method, or an amount of a reactive gas introduced is controlled. For example, in order to change the amount of carbon added, the amount of the raw material or the amount of the saturated hydrocarbons such as methane and ethane, the unsaturated hydrocarbons such as ethylene and propylene, and the amount of carbon dioxide used as the reaction gas to be introduced may be changed. It is also possible to change the excitation conditions when these gases are turned into a plasma state.

The change in the composition concentration of the thin film in the present invention is as follows.
It changes continuously in the film thickness direction, and this change is periodic. The term “periodic” refers to a state in which the changing shape of the composition concentration is repeated in a similar pattern. The shape of the change is not particularly limited, but pseudo, triangular, sine, square, rectangular, or
The rising and falling edges of the square wave may be inclined. Of course, the present invention is not limited to these, and includes a case where the change shape is disturbed. That is, the amplitude and the period need not be constant. In order to achieve the film, it is particularly important to adjust the time division of heating as well as the distance between the two deposition materials.

The concentration of the unit composition element in the present invention can be measured by Auger spectroscopy, X-ray photoelectron spectroscopy (ESCA), secondary ion mass spectrometry (SIMS), or the like. The average concentration of the constituent elements of the present invention is obtained by dividing the sum of the maximum concentration and the minimum concentration measured by ESCA or the like in the thickness direction of the thin film by two. In the present invention, the concentration of any one of the constituent elements is 10
It needs to change by more than%. That is, when the change is less than 10%, the effect of the present invention is hardly obtained. Desirable change in the composition concentration is 10% or more, more preferably 15% or more, even more preferably 20% or more with respect to the average concentration. The upper limit is not particularly limited as long as it is a compound or a mixture thin film.

In the present invention, one cycle refers to the range from the peak of the change in the concentration of the constituent element to the next peak. In the present invention, by having two or more cycles of change, the compound or the mixture thin film can be formed. The effect that the composition concentration changes in the film thickness direction is obtained. This effect means that the change period is 1
In a gas barrier film having a thin film of less than 10 times, it is possible to achieve characteristics that are difficult to achieve simultaneously. For example, in the case of a _binary thin film of Al ₂ O ₃ and SiO ₂ , in the region where the SiO ₂ ratio is large, the flexibility is good, but the heat treatment at high temperatures such as boiling and retorting is inferior. On the other hand, in the region where the Al ₂ O ₃ ratio is large, the heat treatment property is good but the flexibility tends to be poor. However, in the present invention, both good characteristics can be compatible. Further, in the case of a binary thin film of CaO and SiO ₂ , the H ₂ O barrier property tends to be improved in a region where the CaO ratio is large, and the flexibility tends to be improved in a region where the SiO ₂ ratio is large, In the present invention, both of these excellent characteristics can be achieved. The same applies to other combinations of materials. On the other hand, the inclination of the change in the thickness direction of the thin film, that is, there is no particular limitation on the change gradient, but if the inclination is too large, the effect of the present invention is clearly exhibited, but the production speed of the gas barrier film is reduced, and The benefits are small. There is no limitation on the case where the change gradient is small, but in the present invention, it is necessary to have at least two or more change periods.

The gas barrier film of the present invention is transparent and has high barrier properties. The oxygen transmission rate of the plastic substrate can be reduced to 1/10 or less, and the water vapor transmission rate can be reduced to 1/5 or less. That is, when the PET film is used as the base material, the oxygen permeability is 5.0 cc / m ² · 24 hrs.
-Atm or less and good water vapor barrier properties. Therefore, the food packaged with the packaging material of the present invention can be stored for a long time. Furthermore, since the stability of the barrier property against mechanical deformation is excellent, there is little deterioration in the laminating step and the printing step, and the processing speed in the step can be increased.
Further, even after the bag is made, unnecessary care is not required for its handling.

The product of the present invention may be used as it is, or may be used by laminating or coating another container polymer film or a thin layer. The usage form of the packaging or gas barrier film using the gas barrier film of the present invention includes bags, lid materials, cups, tubes, standing bags, trays, paper cartons, and the like. In addition, as the contents, snacks, dried foods such as bonito, konjac, water foods such as tsukemono,
There are frozen foods and retort foods. Also, examples of industrial applications are not limited to the following,
Examples include liquid crystal, EL, and other moisture-proof films. Next, the present invention will be described with reference to examples.

(Embodiment 1) As a vapor deposition source, a particulate Al ₂ O ₃ (purity 99.9%) and SiO ₂ (purity 99.9%) having a size of about 3 to 5 mm were used, and an electron beam was used. 12 µm thick PET film (Toyobo Co., Ltd .: E
5007), an aluminum oxide silicon oxide-based gas barrier thin film was formed thereon. The inside of the heart was divided into two by a carbon plate without mixing the vapor deposition materials. The two materials are 3
0 mm, and the distance between the deposition source and the film is 3 mm.
00 mm. One electron gun (hereinafter E) as a heating source
(B gun), each of Al ₂ O ₃ and SiO ₂ was heated in a time sharing manner. At that time, the emission current of the EB gun was 1.5 A, and the heating ratio to Al ₂ O ₃ and SiO ₂ was 5 A.
0:10. The operating frequency of the EB gun at that time was set to 200 Hz, and the film feed speed was set to 200 m / m.
in, the slit width was 150 mm. The temperature of the chill roll was −5 ° C. The film thickness was constant at 800 °. ((Table 1) Examples 1-1 to 5)

The change in the composition concentration of the obtained film was determined by the ESCA
It measured using the measuring device (Shimadzu Corporation: ESCA-850 type). As measurement conditions, Mg-Kα ray was used as a light source,
The output was 8 KV, 3 mA, and the degree of vacuum was 5 × 10 ⁻⁶ Pa. FIG. 1 shows an example of the obtained depth diagram.
It can be seen that the composition changes in the thickness direction and has a periodic structure. The change in the composition concentration of the thin film thus obtained, the rate of change with respect to the average value, and the cycle are summarized,
It is shown in Table 1. The barrier properties of a state in which a thin film was attached to the surface of the PET as it was (hereinafter referred to as a single film) and the barrier property when directly printed on the deposition surface were measured. Further, the printed gas barrier film is dry-laminated with an unstretched polypropylene film (CPP film) having a thickness of 40 μm using a two-component curable polyurethane adhesive (thickness: 3 μm), and then subjected to a boil treatment. (95 ° C × 60min)
The barrier property at the time of performing was also measured.

Next, a measuring method and a processing method will be described. -Oxygen transmission rate measurement method The oxygen transmission rate of the prepared gas barrier film is measured by an oxygen transmission rate measuring apparatus (OX-TRANS manufactured by Modern Controls).
10 / 50A).・ Measurement method of water vapor transmission rate The water vapor transmission rate of the prepared gas barrier film is set to 40 ° C.
It was measured at 90% RH according to the test method of (JIS K7129). As a measuring instrument, a water vapor permeability tester (L80-4000, manufactured by RISSI) was used.

Printing Method Using a gravure printing machine, printing was directly performed on the vapor deposition surface, and the barrier property was measured as it was. The ink used was NewLP Super R162 Red manufactured by Toyo Ink Co., Ltd., and the printed pattern was solid. The feed speed of the film was 50 m / min. The oxygen transmission rate (Table 1) measured in this way was as excellent as about 1 cc after boiling. In addition, the result after printing was only about a rise of about 2 cc, and a gas barrier film having both heat treatment properties and flexibility was obtained.

Comparative Example 1 A silicon oxide-based gas barrier thin film was formed by a resistance heating evaporation method. The obtained sample was subjected to measurement of oxygen barrier properties after printing and lamination in the same manner as in (Example 1). As a result, the barrier properties after printing became insufficient, and the properties after lamination were not so good. (Table 1) (Comparative Example 2) A laminated gas barrier thin film of an aluminum oxide thin film and a silicon oxide thin film was formed on a PET film (Toyobo Co., Ltd .: E5007) having a thickness of 12 µm by the EB vapor deposition method. Put Al ₂ O ₃ and of SiO in separate crucibles, first, Al ₂ O ₃ is heated, Al ₂ O ₃ on a PET film
A thin film (1000 mm thick) was applied. Next, the film is run in the reverse direction, and this time, the SiO is heated,
l wearing a SiO thin film (1000Å thick) on top of the ₂ O ₃ thin film. Similarly, an Al ₂ O ₃ thin film (1000 mm thick)
To finally obtain a gas barrier film having a structure of Al ₂ O ₃ / SiOx / Al ₂ O ₃ . At that time, the emission current of the EB gun is 1.2 A for Al ₂ O _{3 and} 05 A for SiO. Film feed speed 100m /
min. The temperature of the chill roll was −5 ° C. The film thickness was constant at 800 °. ((Table 1))

Comparative Example 3 An aluminum oxide silicon oxide gas barrier thin film was formed in the same manner as in Example 1.
The conditions for the creation were as follows: the emission current of the EB gun was 0.8
１．５1.5 A, and the heating ratio of Al ₂ O ₃ to SiO ₂ is 7
The operation frequency was 50 to 200 Hz, the film feed speed was 60 to 200 m / min, and the slit width was 150 mm. The two materials were separated by 5 mm and the distance between the deposition source and the film was 300 mm. The temperature of the chill roll was −5 ° C. 800Å
It was fixed. ((Table 1) Comparative Examples 3-1 and 2) Table 1 shows the results obtained by measuring the change in composition concentration and the period of the obtained film using an ESCA measurement apparatus. (Example 1)
In the same manner as in Example 1, the barrier property after printing and after lamination was measured. (Table 1) As a result, the barrier properties after printing were insufficient, and the properties after lamination were not so good.

Example 2 As vapor deposition sources, particulate CaO (purity 99.9%) and Si having a size of about 3 to 5 mm were used.
Using O ₂ (purity 99.9%) by electron beam evaporation,
12 μm thick PET film (Toyobo Co., Ltd .: E50
07), a transparent gas barrier thin film was formed thereon. The evaporation material was not mixed, and one EB gun was used as a heating source.
Heating was performed at an operating frequency of 20 to 60 Hz. The emission current was 1.5 A, and the heating power ratio was changed to 40:10. Here, the distance between the two materials was the same as in Example 1. The chill roll temperature was -5C. Set the film feed speed to 150 m / min and set the slit width to 100
mm. A 1000 mm thick film was made. (Example 2
1-4) The vapor pressure was 4 × 10 ⁻⁴ Torr with the supply amount of oxygen gas being 100 ccM. The change in composition in the thickness direction, the period, and the barrier properties of the obtained film were measured in the same manner as in Example 1. Table 2 shows the results. The oxygen permeability measured in this manner was very excellent, being 1 cc or less after lamination. Further, the result after printing was 2 cc or less, and a gas barrier film having excellent overall characteristics was obtained.

Comparative Example 4 In the same manner as in Example 2, a CaO—SiO ₂ -based gas barrier thin film was formed by the EB heating evaporation method. At this time, the emission current of the EB gun was 0.8 A, the operation frequency was 20 to 100 Hz, the film feed speed was 80 m / min, and a film having a thickness of 1000 mm was formed.
Here, the distance between the two materials was the same as in Comparative Example 1. For the obtained sample (Comparative Examples 4-1 and 2),
As in Example 2, the composition change in the thickness direction and the barrier characteristics were measured. As a result, the properties after printing and after lamination became insufficient.

The unstretched polypropylene film (C) having a thickness of 40 μm was compared with the samples of Examples 2-1 to 4 and Comparative Examples 4-1 and 2 in which the printed sample was dry-laminated.
The PP film) was dry-laminated using a two-component curable polyurethane adhesive (thickness: 2 μm) to obtain a plastic film for packaging according to the present invention. Using this plastic film for packaging, heat sealing,
A bag having a size of 200 × 180 mm was formed. 100 g of potato chips were sealed in this bag together with nitrogen gas, left in a room of 40 × 90% RH for 9 months, opened, tasted, and examined for taste, flavor, and chewyness. As a result, it was determined that the example of the present invention was normal, but the potato chips in the comparative example were slightly damp, had no chewy texture, and had a poor taste.

Example 3 A 12 μm-thick PET film (Toyobo Co., Ltd.) was used as an evaporation source by EB heating evaporation method using particulate SiO (purity 99.7%) having a size of about 3 to 5 mm. ): Silicon oxide (Si) on E5001)
Ox) A gas barrier thin film was formed. A film feeding speed of 100 m / min and an applied power of 5 kW were used to form a film having a thickness of 800 °. (Examples 3-1 to 3) In addition, propylene gas was used as a reaction gas, and a high-frequency voltage was applied to an electrode installed near a chill roll so that carbon substitution proceeded smoothly, and the propylene gas was brought into a plasma state. . The flow rate is changed and the amplitude is 5 around the excitation voltage of 1 KV.
It was changed by a sin curve at 00V. The carbon substitution amount and the change in the thickness direction of the film thus obtained were measured using an ESCA apparatus. The measurement conditions were as follows: Mg-Kα ray as a light source, output 8 kV × 30 mA, vacuum degree 5 × 10 ⁻⁶ P
a was fixed. Further, the barrier characteristics were measured in the same manner as in Example 2. (Table 3) The oxygen permeability measured in this way was very excellent, being 1 cc or less after lamination. Further, the result after printing was 2 cc or less, and a gas barrier film having excellent overall characteristics was obtained.

Comparative Example 5 A thin film in which a part of a silicon oxide-based gas barrier thin film was replaced with carbon was manufactured by the EB heating evaporation method in the same manner as in (Example 3). The excitation voltage was kept constant at 1 KV without changing the propylene gas flow rate. The carbon substitution amount, composition change in the thickness direction, and barrier properties of the obtained sample were measured. As a result, the barrier properties after printing and after lamination were insufficient. (Table 3)

[0028]

According to the present invention, at least one surface of the plastic substrate is
In a gas barrier film on which a compound or mixture thin film is formed, the concentration of any of the constituent elements in the thin film changes by 10% or more in the thickness direction with respect to the average concentration of the constituent elements, and the period of the change is 2%. When the number of times is equal to or more than the number of times, a gas barrier film having excellent gas barrier properties and excellent overall properties in which two properties such as heat treatment properties and flexibility are compatible can be provided.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Table 3]

[Brief description of the drawings]

FIG. 1 shows an example of measurement of a change in composition concentration in a film thickness direction by ESCA.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toshio Uno 2-1-1 Katata, Otsu-shi, Shiga Prefecture Inside Toyo Spinning Co., Ltd. (72) Inventor Yozo Yamada 2-1-1 Katata, Otsu-shi, Shiga Prefecture Hiroaki Hirai, Examiner, Research Laboratory, Toyobo Co., Ltd. (56) References JP-A-5-338072 (JP, A) JP-A-5-338073 (JP, A) JP-A 5-339704 (JP, A) JP-A-3-64449 (JP, A) JP-A-2-194944 (JP, A) JP-A-60-189704 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1 / 00-35/00 C23C 14/00-14/58

Claims (3)

(57) [Claims] 1. A method according to claim 1, wherein at least one side of the plastic substrate has
In a gas barrier film on which a thin film of a compound or a mixture of two or more elements or oxides thereof is formed, the concentration of any one of the constituent elements in the thin film is 10% in the thickness direction with respect to the average concentration of the constituent elements. Change
And a cycle of the change is two or more times. 2. A heat sink on the thin film layer according to claim 1.
A gas barrier film, wherein a gas layer is provided. 3. A film for packaging or gas shielding using the gas barrier film according to claim 1 or 2.