JPH1053861A - Production of aluminum oxide vapor-deposited film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a transparent aluminum oxide vapor-deposition film having stable performance on a continuous film by heating and evaporating aluminum by the irradiation of electron beams in a vacuum tank and introducing a specified amt. of oxygen therein. SOLUTION: In a vacuum tank 1, a continuous plastic film 5 is run along a cooling drum 3 of about -30 to 10 deg.C. Furthermore, aluminum housed in a crucible 6 is heated and evaporated by the irradiation of electron beams from an electron beam gun 11. To this aluminum vapor, oxygen introduced from a gas blow-off outlet 8 is fed, and they are brought into reaction with each other. At this time, vapor deposition is executed in such a manner that B/A, i.e., the ratio of the amt. of oxygen to be introduced B (mol/min) to the amt. of aluminum to be evaporated A (mol/min) is held to 0.01<=B/A<=0.2. In this way, the oxygen excited by the electron beams is effectively brought into reaction, by which the aluminum oxide vapor-deposition film in which a trace amt. of Al is present in Al2 O3 and excellent in gas barriering properties and transparency can be obtd. by a uniform thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a deposited aluminum oxide film, and more particularly to a method for producing aluminum oxide by using aluminum as an evaporation source and effectively depositing aluminum oxide on a continuous plastic film.

[0002]

2. Description of the Related Art A vapor-deposited film in which aluminum oxide is vapor-deposited on a continuous plastic film is disclosed in JP-A-58-1983.
As shown in No. 2173, it is already known as a gas barrier film.

[0003] As a method for producing this aluminum oxide deposited film, a method using aluminum oxide itself as an evaporation source is generally used. However, when aluminum oxide was used as the evaporation source, there were problems that the vapor pressure was low and that evaporation had to be performed at a high temperature.

[0004] Therefore, there is known a method of producing an aluminum oxide vapor-deposited film by a so-called reactive vapor deposition method in which aluminum is used as an evaporation source and vapor deposition is performed while introducing oxygen gas into aluminum vapor. This reactive deposition method
Since vapor deposition is performed while introducing oxygen into the vacuum chamber, the ratio between the supplied oxygen amount and the aluminum evaporation amount becomes important. By specifying the ratio between the supply amount of oxygen and the evaporation amount of aluminum, the pressure in the vacuum chamber can be kept within a certain range, and an aluminum oxide layer having a uniform thickness is deposited on a plastic film. A method has been proposed. (See Japanese Patent Publication No. 6-99798)

On the other hand, considering the method of supplying oxygen and the method of evaporating aluminum (electron beam irradiation heating method, resistance heating method), 50% or less of the evaporated aluminum is
In addition to depositing on the plastic film, the supplied oxygen reacts only with the aluminum deposited on the plastic film, so the amount of oxygen supplied should be set to a corresponding range of amounts that will react with the deposited aluminum. There must be. In a state where the supply ratio of oxygen is excessive as compared with the adhered aluminum, the balance of the vapor deposition atmosphere in the vacuum chamber is lost, so that a gas barrier property and the production of an aluminum oxide vapor-deposited film having an aluminum oxide layer with a uniform thickness are produced. Becomes difficult.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for continuously depositing aluminum oxide on a continuous plastic film while supplying oxygen into a vacuum chamber using aluminum as an evaporation source. An object of the present invention is to provide a method for producing an aluminum oxide vapor-deposited film, which enables vapor deposition having an aluminum oxide vapor-deposited layer having stable performance even in a state where the amount is as small as possible.

[0007]

According to the present invention, aluminum is irradiated with an electron beam and heated and evaporated while introducing oxygen into a vacuum chamber, and an aluminum oxide vapor-deposited layer is continuously formed on a continuous plastic film. In the method for producing an aluminum oxide deposited film to be formed, the ratio [B / A] between the average aluminum evaporation amount per unit time A [mol / min] and the oxygen introduction amount per unit time B [mol / min]
Is carried out while maintaining 0.01 <B / A ≦ 0.2. Further, a second invention is a method for producing an aluminum oxide vapor-deposited film, in which the vapor deposition is performed in an atmosphere in which microwave plasma is generated.

[0008]

Since the vapor deposition of aluminum is performed by irradiating an electron beam, not only the heating of the vapor deposition source, but also the oxygen supplied to the vacuum chamber is excited and reacts with the evaporated aluminum more reliably. By supplying a small percentage of oxygen, a transparent aluminum oxide deposited film having excellent gas barrier properties can be produced.

Further, since the deposition atmosphere is further excited by the microwave plasma, a transparent aluminum oxide deposited film having excellent gas barrier properties can be produced with a smaller proportion of oxygen.

[0010]

FIG. 1 is an explanatory view showing an example of a reactive vapor deposition apparatus according to the present invention. The continuous plastic film 5 wound around the winding shaft 2 installed in the vacuum chamber 1 is -3.
While running along the cooling drum 3 cooled to 0 ° C. to 10 ° C., the film is wound around a film winding shaft 4. At the same time, the electron beam gun 7 irradiates the aluminum in the crucible 6 with an electron beam to evaporate the aluminum and supply oxygen from a gas outlet 8 located in a vapor atmosphere of aluminum.

The evaporated aluminum reacts with oxygen,
An aluminum oxide deposited film is formed on the surface of the plastic film 5. Here, aluminum oxide is Al
O, shows a Al ₂ O _3, instead of completely Al ₂ O _3, a state where there is Al traces the Al ₂ O ₃ is, gas barrier properties, is a good state transparency. Further, by supplying a microwave to the horn antenna 11 for generating a plasma in the evaporated aluminum, vapor deposition can be performed more effectively.

A specific example of the present invention using the above-described vapor deposition method will be described. A polyester film having a width of 50 cm (thickness: 12 μm) is run at a speed of 600 m / min, and an aluminum oxide layer having a thickness of 400 ° is deposited on the polyester film. 3 g / min (4.0 mol / min), while the supply amount B of oxygen was 8 to 13 liter / min (0.477 to 0.774 mol / min). That is, the oxygen supply amount B / aluminum evaporation amount is set to 0.12 to
The test was performed under the condition that the range was 0.19. At this time, the vaporized aluminum was set to have an adhesion efficiency of 30% as aluminum oxide on the polyester film, and the oxygen supply amount was set so as not to be excessive.

The aluminum oxide deposited film deposited under the above conditions was a film that was transparent, had excellent gas barrier properties, and had little variation in film thickness.

[0014]

According to the present invention, since the ratio of the supply amount of oxygen to the evaporation amount of aluminum is made small,
Since the supply amount of oxygen does not become excessive and the pressure balance in the vacuum chamber is not lost, a continuous deposited film having a stable film thickness can be obtained.

Further, by performing the vapor deposition under the conditions of the present invention, the aluminum oxide formed by vapor deposition completely becomes Al ₂
Since vapor deposition is performed in which a small amount of Al is present instead of O ₃ ,
An aluminum oxide vapor-deposited film having excellent gas barrier properties without impairing transparency can be produced.

[0016] Furthermore, this is a vapor deposition method by electron beam irradiation, which can perform reactive vapor deposition with a smaller supply amount of oxygen and generate plasma in a vapor deposition atmosphere to more effectively produce an aluminum oxide vapor deposited film. It has become possible.

[Brief description of the drawings]

FIG. 1 is an explanatory view schematically showing an apparatus for producing a vapor deposition film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Vacuum tank 2, 4 ... Winding axis 3 ... Cooling drum 5 ... Plastic film 6 ... Crucible 7 ... Electron beam gun 8 ... Gas outlet 11 ... Horn antenna

Claims (2)

[Claims] An aluminum oxide-deposited film for continuously forming an aluminum oxide-deposited layer on a continuous plastic film by irradiating an electron beam to the aluminum while heating and evaporating the aluminum while introducing oxygen into the vacuum chamber. In the method, the average aluminum evaporation amount per unit time A
The ratio [B / A] of [mol / min] to the oxygen introduction amount B [mol / min] per unit time is 0.01 <B / A ≦ 0.
2. A method for producing a vapor-deposited aluminum oxide film, comprising performing vapor deposition while maintaining the film thickness at 2. 2. The method according to claim 1, wherein the deposition is performed in an atmosphere in which microwave plasma is generated.