JPH0759748B2 - Method for manufacturing composite film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a method for producing a composite film in which a thin film layer of a metal, a metal compound, a silicon oxide or the like is provided on a polymer substrate.

In particular, the present invention relates to a method for producing a composite film in which the adhesion between a polymer substrate and a thin film layer is provided and which is excellent in moisture resistance and oxygen barrier properties.

<Prior Art> In the field of pharmaceutical food packaging, there are various physical properties imparted to packaging materials from the viewpoint of content protection, and required physical properties are becoming severe.

In particular, in terms of protecting the contents, from the viewpoint of preventing alteration and oxidation of the contents, it has become indispensable to impart oxygen barrier properties and water vapor barrier properties to packaging materials.

Nowadays, such imparting of barrier properties is becoming popular, and the packaging material is designed on the basis thereof.

Generally, from the viewpoint of oxygen barrier property, ethylene vinyl alcohol copolymer, polyvinyl alcohol formal compound (vinylon), biaxially oriented polyamide (ONy)
Unstretched polyamide (CNy), cellophane, etc. are excellent.

From the viewpoint of water vapor barrier properties, biaxially oriented polypropylene (OPP), unoriented polypropylene (CPP), etc. are excellent.

On the other hand, those having both oxygen and water vapor barrier properties are so-called K coated with various films such as polyvinylidene resin and polyvinylidene polyacrylic acid copolymer resin.
There are cellophane, KOP, KPET, KONy, K vinylon.

However, these are inferior to aluminum foils in terms of light-shielding property and aroma-storing property, and although the individual materials mentioned above have their respective advantages, they cannot have all physical properties by themselves.
By stacking two or more kinds of different materials, they are used as a laminate having a composite function.

On the other hand, aluminum foil is extremely excellent in both physical properties of water vapor and oxygen barrier, and has a display effect in terms of glossiness, but if it is 20 μ or less, it is pinhole resistant, and recently from the viewpoint of cost, PET, So-called metal-deposited films in which aluminum or the like is vacuum-deposited on a substrate such as ONy, OPP, and CPP are actively used in terms of moisture-proof, oxygen-barrier property, light-shielding and aroma-retaining display effect.

However, when such a metal vapor deposition film is used as a packaging material, the transparency cannot be confirmed such that the contents cannot be confirmed and it cannot be heated in a microwave oven, and when it is used as a vapor deposition film for retort food packaging, etc. After retort sterilization, Al
There is a problem in that the vapor deposition layer is cracked and peeled off.

In order to solve such problems, a vapor deposition anchor layer is provided, a protective layer is provided on the Al vapor deposition layer, or Al
Many studies have been conducted on a method of making the vapor deposition layer transparent by oxidizing the vapor deposition layer. (For example, Japanese Patent Publication No. 62-49856) In addition, transparent silicon oxide (SixOy x =
1-2, Y = 0 to 3) A vapor-deposited film provided with a moisture-proof property and an oxygen barrier property by forming a thin film on a polymer substrate is also on the market. (For example, Japanese Examined Patent Publication No. 53-12953) However, the above-mentioned silicon oxide (thin film) vapor-deposited film has an optimum vapor-deposited film thickness that does not impair the flexibility of the polymer substrate and can impart moisture resistance and oxygen barrier properties. Not clear. In addition, when laminated with an olefin such as polyethylene or polypropylene with an adhesive or the like and used as a retort sterilization packaging material for food, after the retort, the adhesion between the vapor-deposited film and the polymer base material is insufficient. There have been major problems such as cracks in the film, which greatly deteriorates the gas barrier property.

<Problems to be Solved by the Invention> The present invention is to solve the above-mentioned conventional drawbacks, and an object thereof is to provide a composite film having excellent adhesion between a vapor deposition film and a polymer substrate. It is a thing.

<Means for Solving Problems> In the present invention, a polymer film continuously supplied in a vacuum system is heated to a temperature not lower than a glass transition temperature of the polymer film, not by a normal cooling roll. The object can be achieved by providing a thin film layer of a metal, a metal compound, or a silicon oxide on the polymer film while contacting and heating a heating roll.

In addition, after forming a thin film of 100 Å or less composed of a metal or a metal compound on a polymer film continuously supplied in a vacuum system, a silicon oxide (SixOy x =
The objective can be achieved at the same time by forming a transparent thin film layer of 1 to 2, Y = 0 to 3).

The polymer film used in the present invention includes polyvinyl chloride, polyethylene, polyester film, polyvinyl butyral, ponyethylene, polypropylene, polyamide, polycarbonate cellophane, etc., which may be used alone or in a laminate, and is usually The thickness is preferably 5 to 300 μm, preferably 6 to 100 μm, and a printing layer for pictures, characters, etc. may be provided if necessary.

Next, the manufacturing method of the present invention will be described with reference to the drawings.
First, as shown in FIG. 1, this polymer film (1) is in a vacuum system (2), and several control rolls (4), dancer rolls (5) and expander rolls ( While passing through 6) and being heated by contacting with a heating roll (7), a metal or metal is applied to the surface of the polymer film by a resistance heating method, high frequency induction heating direct current bipolar sputtering, high frequency sputtering means, ion plating or the like. A thin film layer of a compound, silicon oxide, etc. is continuously provided, and similarly, it passes through several rolls and a winding roll (8)
It is wound up at a constant speed. In this case, a cooling drum (9) may be provided after the heating roll (7) if necessary. The temperature of the heating roll varies depending on the type of polymer film used, but in any case, it is considered that there is a close relationship with the glass transition temperature of the polymer film, and in view of the heat resistance of the polymer film, the temperature is infinite. The temperature range (A) of the heating roll is different from the glass transition temperature (Tg) of the polymer film depending on the type of the polymer film (Tg-30) ° C A (Tg).
+50) ° C, preferably (Tg-10) ° C A
(Tg + 10) ° C.

The heating roll is a means for instantly raising the temperature of the film to a glass transition temperature or higher when forming a thin film on the polymer film, and the surface temperature of the polymer film is raised to the glass transition temperature or higher by another method. However, it does not matter, any means may be used.

Metals, metal compounds and silicon oxides that can be used in the present invention are Li, Be, Na, Mg, Al, Si, K, Ca, Ti, V, Cr, Mn, Fe, Co,
Ni, Cu, Zn, Ga, Ge, Se, Zr, Nb, Mo, Ag, Cd, In, Sn, Sb, Te, Ba, T
a, W, Au, and other metals and AlN, BN, Si ₃ N ₄ , Al ₂ O ₃ , BeO, SiO,
SiO ₂ , Si ₂ O ₃ , TiO ₂ Ta ₂ O ₅ , PbO, MgO, Zr ₂ O ₃ , BaTiO ₃ , Fe ₂ O ₃ such as oxides, nitrides, etc. .

In the present invention, when the thin film-forming metal, metal compound, and silicon oxide fine particles are laminated and formed into a film on the polymer film, the polymer film has a sufficiently short time that heat shrinkage or the like does not occur. It is necessary to be sufficiently cooled by the cooling roll in order to take contact with the heating roll and heat strain.

Further, the film thickness of the metal, metal compound, and silicon oxide thin film layer of the present invention is 100 Å or more and 5000 Å or less, and the optimum film thickness is 500 Å or more and 2000 Å or less. If it is 100 Å or less, the film structure will not be formed, and if it is 5,000 Å or more, there is a difference from the thermal expansion coefficient of the polymer film, and thus cracks such as cracks will inevitably occur, which is not preferable.

And another aspect of the present invention is vacuum deposition on a polymer film surface as described above in a vacuum system, sputtering,
Metal by general PVD method such as ion plating,
After forming a thin film of 100 Å or less, such as a metal compound, in-line in the same vacuum system, the silicon oxide (SixOy
x = 1 to 2, Y = 0 to 3) A thin film layer is formed by the PVD method described above.

Specifically, on at least one surface of the polymer film described above, Al, Cu, Cr, Fe, Ni, Ti, Ba, Mg, Zr, In, Ca, Zn, S
n, W, Co, etc., or one or more thin films selected from their oxides, nitrides, etc., 100 Å or less, preferably 5
A film is formed below 0 Å by any one of vacuum vapor deposition, sputtering method, and ion plating method.

Preferably the oxide formation energy is -471.0 Kcal / mol
Ta, −376.7 Kcal / mol Al, −250.0 Kcal / mol Cr, −20
4.0 Kcal / mol Ti, −182.5 Kcal / mol W, −51.7 Kcal / mol
Ni-51.0 Kcal / mol Co, -161.9 Kcal / mol Mo, Na, Si, etc. are small, especially Al, Co, Cr, MO,
Ni, Ta, Ti, W are excellent.

In any case, it is necessary to deposit SiO 2 by a means such as vapor deposition while the metal of the metal thin film is active before being oxidized.

The thickness of the silicon oxide thin film used in the present invention is 100Å
It is preferably 5000 Å or more and 500 Å or more and 2000 Å or less as an optimum film thickness that does not impair the flexibility of the polymer film and has very little barrier deterioration after retort. If the film thickness is less than 100Å, the film will have an island structure, resulting in insufficient moisture permeation resistance and gas barrier properties.
If it exceeds 00Å, the flexibility inherent in the polymer film will be lost, and the thin film provided on the film will be cracked, and on the other hand moisture resistance and gas barrier properties will decrease, and the high Adhesion to the molecular film is reduced.

The present invention further improves the adhesiveness with a thin film formed by performing a discharge treatment in a vacuum system as a pretreatment of the polymer film.

The discharge treatment of the present invention refers to a discharge treatment in a vacuum system, that is, in a gas mixture of 1 × 10 ⁻³ Torr to 10 Torr of oxygen, nitrogen, argon, helium, or a mixed gas containing them. The purpose can be achieved by exposing a plasma discharge generated by applying a microwave or a cross flow and exposing the polymer film in such a plasma discharge atmosphere for a certain period of time.

In low temperature plasma with high frequency and microwave application, the discharge characteristics differ depending on the type of gas pressure used,
Generally, 500 to 1000 W or more for 1 second or more, preferably 1000
Processing time of several seconds or more is required at W. Also in the latter cross-flow application type discharge treatment, the discharge characteristics differ depending on the type pressure of the gas used, but the treatment time is 1 second or more, preferably several seconds under any condition of 50 W or more and 400 W or less. In this case, the main effect of the discharge treatment is contamination of the surface of the polymer film, cleaning of charged particles and the like, and it is preferable to use an inert gas such as Ar as a gas.

<Operation> First, with the surface temperature of the polymer film forming the thin film layer heated to a temperature near the glass transition temperature, a metal, a metal oxide, or a silicon oxide is formed by any one of vacuum deposition, sputtering, and ion plating. When a thin film layer of a substance is formed, a micro-Brownian motion of a polymer film amorphous that is instantaneously heated above the glass transition temperature is started, an anchor effect occurs on the polymer film surface, and a metal, a metal compound, Alternatively, the silicon oxide excited particles collide with the surface of the polymer film to bond with active gases such as oxygen and carbon dioxide, which are present in the vacuum system in a trace amount, on the surface of the polymer film, thereby forming a polymer constituting the polymer film. Hydrogen bonds and secondary bonds with functional groups (dispersion force, orientation force, induction force)
A thin film layer which is stabilized by the above and has sufficient adhesion is formed on the polymer film.

Further, in the same manner as above, after performing a pretreatment of once providing a metal thin film layer on the polymer film, when providing a silicon oxide thin film layer, after performing the pretreatment of the metal thin film layer, return to atmospheric pressure once. Then, even if the SiO film is formed again, the metal active layer is stabilized by oxidation in advance, so that the metal-SiO adhesion does not increase so much and the effect is small.

By providing a metal thin film layer of 100 Å or less on the polymer film, brings an anchor effect on the film, and
Since it is a very thin layer, the light transmittance in the visual area is sufficiently high, and a composite film having sufficient adhesion between the polymer film and the silicon oxide thin film can be obtained without affecting transparency.

Examples of the present invention will be described below.

<Example-1> The vacuum deposition apparatus shown in FIG. 2 (SPW manufactured by Nippon Vacuum Technology Co., Ltd.
-020), the continuous glass transition temperature is 6
9 ℃ polyethylene terephthalate film (12μ)
(PET) (NS manufactured by Teijin Ltd.) is installed on the unwinding (3) side, and 250 g of 4N aluminum is put into the vapor deposition source (10) using an electron beam heating (11). ), Using an oil rotary pump and an oil diffusion pump, 4.2 x 10
^{Evacuated to -5} Torr vacuum.

An aluminum vapor deposition film was obtained under the following conditions, and the aluminum vapor deposition film was about 400Å.

Next, this aluminum vapor-deposited film and unstretched polypropylene (CPP) (Showlex Allomer AT, manufactured by Showa Denko) were dry-laminated using a urethane adhesive and a 135 μ-75 l grid plate.

(Deposition conditions) (Lamination conditions) The resulting laminated film was made into a bag of 150 × 150 m / m,
Fill the contents with 300 cc of tap water and load this at 125 ° C for 20 minutes at 2.1 KgG.
The retort sterilization treatment was performed under the conditions of / cm ² and two-stage cooling (cooling time 5 min), and then the adhesion strength between the aluminum vapor deposition film of the laminated film and PET was evaluated using an Instron type tensile tester.

(Example-2) Using SiO (200Mesh or less manufactured by Osaka Titanium) as the vapor deposition,
The heating roll temperature was kept at 70 ° C., the vapor deposition conditions were set as follows, and the same test as in Example-1 was conducted.

At this time, the SiO vapor deposition film thickness was about 1200Å. In addition, the oxygen barrier property, the water vapor barrier property, and the adhesion strength between the SiO film and PET after lamination and after retort sterilization were evaluated in Example-1.
It evaluated using the Instron type tensile testing machine like the above.

(Example-3) A thin film of Al was PET-coated by sputtering in the same vacuum system.
(NS, manufactured by Teijin) (12μ), then vapor-deposited SiO in the same manner as in Example-2, further laminated with CPP and retort sterilized in the same manner as in Example-1, and evaluated the following physical properties. did.

The sputtered film thickness formed on PET was 17-25Å as calculated by ICP emission analysis with Al density of 2.7 g / cm ² .

The SiO film was about 1350Å.

<Comparative Examples-1 to 6> The same evaluation was performed as in Example 1 except that the heating roll temperature was set to -10 ° C, 0 ° C, 10 ° C, 20 ° C, 30 ° C, 40 ° C. .

(Comparative Examples-7 to 12) The heating roll temperature was set to -10 ° C, 0 ° C, 20 ° C, 40 ° C, 100 ° C and other conditions were evaluated in the same manner as in Example-2.

(Examples 4 to 10) Instead of the Al thin film of Example-3, Co, Ni, Cr, Ta, W, respectively.
A thin film pretreatment of Mo was performed, and thereafter SiO vapor deposition was performed in the same manner, and evaluation was performed.

In the test by the metal thin film pretreatment of Examples-4 to 10, the metal thin film layer is the result obtained by calculating from the ICP emission analysis result and the density of each bulk, and the results are as follows, all of which are extremely thin below 100Å It was a layer.

Example-4 CO layer ...... 25 to 30Å Example-5 Ni layer ・ ・ ・ 31 to 50Å Example-6 Cr layer ・ ・ ・ 19 to 26Å Example-7 Ta layer ・ ・ ・ 39 to 63Å Example-8 Ti layer ...... 22 to 44Å Example-9 W layer ...... 16 to 20Å Example-10 Mo layer ...... 30 to 70Å The thin film layer of each sample was measured for the thickness difference by a mechanical stylus method. (Dectak II, manufactured by Nippon Vacuum Co., Ltd.) <Example-11> 12 μm of PET (NS Teijin) was subjected to low-temperature plasma treatment using the apparatus shown in FIG. 1 under the following conditions, and then SiO vapor deposition was performed as in Example-3. I evaluated it. Heating roll temperature is 50 ℃
Set to.

Gas used ... O ₂ vacuum ... 0.1 Torr output ... 1000W speed ... 1 m / min (Toshiba TMZ-4072 used) <Example -12> Example -2 and similar in the evaporation material Si ₃ N ₄ (manufactured by Ube Industries, Ltd. ) And the heating roll temperature was set to 70 ° C., the same test as in Example 2 was carried out.

The gas used in the same conditions as <Example -13,14,15,16,17> Example 11 Air, a SiO thin film layer formed on the PET using _{N 2, Ar, He, Ne} , a similar An evaluation was performed.

<Example-18> Ar gas was introduced into the electric discharge treatment space of the apparatus of FIG. 1 to perform electric discharge treatment on the polymer film, and then a SiO vapor deposition film was formed under the same conditions as in Example 3 An evaluation was performed.

<Effects of the Invention> As described above, by forming a thin film layer of a metal, a metal compound, or a silicon oxide while heating a polymer film, it is excellent in adhesiveness with the polymer film and has moisture resistance with retort resistance. And a composite film having an excellent oxygen barrier property was obtained.

Also, by providing a polymer film with a metal or metal compound thin film layer of 100 Å or less and then sequentially laminating silicon oxide thin films, there is transparency. Even after retorting, the adhesion between the polymer film and the thin film layer is extremely high. In addition, a highly practical composite film with extremely little deterioration in moisture resistance and oxygen barrier property was obtained.

Furthermore, a polymer film is subjected to discharge treatment by the above method, and then a thin film of a metal, a metal compound, or a silicon oxide is provided, so that the adhesion between the film and the thin film layer is extremely excellent and a highly useful composite. A film was obtained.

Thus, the composite film obtained by pre-treating the polymer film and providing the thin film of metal, metal compound, silicon oxide and the like on the polymer film has excellent adhesion of the thin film, and packaging When used as a material, a gas barrier property after retort and moisture resistance are less deteriorated, and a composite film having sufficient practical adhesive strength is obtained.

[Brief description of drawings]

1 and 2 are schematic explanatory views of a thin film forming apparatus used in the manufacturing method of the present invention. 1 ... Polymer film, 2 ... In vacuum system 3 ... Unwinding roll, 4 ... Control roll, 5 ... Dancer roll, 6 ... Expander roll, 7 ... Heating roll, 8 ... Winding roll, 9 ... … Cooling roll, 10 …… Deposition source 11 …… Deposition source power

Claims (3)

[Claims] 1. Vacuum heating of metal, metal oxide, and silicon oxide while heating the surface temperature of the polymer film to a temperature of (T _g −30) ° C. or higher and (T _g +30) ° C. or lower in a vacuum system. A method for producing a composite film, which is formed by any one of vapor deposition, sputtering, and an ion plate. 2. A silicon oxide (Si _X O) is formed on a polymer substrate on which a thin film of 100 Å or less composed of metal or metal oxide is formed.
_y X = 1 to 2, y = 0 to 3) The method for producing a composite film according to claim 1, wherein the thin film layer is provided. 3. The method for producing a composite film according to claim 1, wherein the polymer base material is subjected to electric discharge treatment in a vacuum system.