JP2000008161A - Film producing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film producing device for food packing capable of inexpensively producing a film for food packing provided with excellent properties in large quantities. SOLUTION: This device is approximately composed of a carrying system composed of plural rolls (1, 5 and 9) including a a vapor depositing roll 5, a vacuum tank, a crucible, a gaseous oxygen nozzle 10 and a plasma generating means. Into the space between the vapor depositing roll 5 and the crucible, microwaves oscillated from a microwave oscillator 12 are introduced, and gaseous oxygen fed from the gaseous oxygen nozzle 10 is made in a plasma state. Aluminum evaporated from the crucible is brought to react with this oxygen plasma and is vapor-deposited as aluminum oxide onto a plastic film 2 on the vapor depositing roll 5 Moreover, high-frequency voltage is applied to the vapor depositing roll 5, and energy is given to electrons and ions in the plasma.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film manufacturing apparatus for manufacturing a film having high shielding performance against the outside air by depositing aluminum oxide or the like on the surface.

[0002]

2. Description of the Related Art FIG.
And what is shown in FIG. 3 is proposed.
These are generally referred to as continuous-type and FIG. 3 batch-type film manufacturing apparatuses, respectively. In any case, the plastic film 2 as the base material is scattered from the evaporation source 6 while being transported through a transport system constituted by a plurality of rolls including the vapor deposition roll 5 (the payout roll 1, the take-up roll 9, and the like). This is an apparatus for depositing vapor of aluminum or the like on the film. In addition, as a specific form of the evaporation source 6, an induction heating crucible is widely used, a method using an electron beam as a heating source, a method using a plasma CVD method, and the like have been proposed.

[0003] As a specific application of the film, a film for food packaging is mentioned as an example. In this food packaging film, a high shielding property against the outside air is required in order to prevent corrosion of the packaged food. Aluminum-deposited film as described above, the oxygen permeability of 1cc / cm ² · day, has excellent gas barrier properties of water vapor permeability of 0.5cc / cm ² · day. Further, the vapor deposition film used as a food packaging film is not limited to the aluminum vapor deposition film, for example, it can be used in a microwave oven, and an aluminum oxide vapor deposition film having a property of being transparent is also provided. I have.

[0004] The above properties of the aluminum oxide deposited film, that is, properties such as availability in a microwave oven and transparency, are not provided in the aluminum deposited film, and thus there is a great need for a film for food packaging. It has become something. However, the aluminum oxide vapor-deposited film has not been widely used because of its inferior gas barrier properties to aluminum vapor-deposited film and high production cost.

[0005] As a method for producing this aluminum oxide vapor-deposited film, aluminum oxide is directly used as an evaporating material, or a film obtained by evaporating aluminum and introducing oxygen gas into a vapor deposition chamber and reacting them is deposited on the film. Methods such as vapor deposition have been considered. A film manufacturing apparatus employing the latter means is shown in FIG. 3 described above, and reference numeral 10 denotes an oxygen nozzle for introducing oxygen gas. The oxygen gas nozzle 10
May be provided in the continuous apparatus of FIG. The aluminum oxide vapor-deposited film produced by this method usually has a gas barrier property of about 5 cc / cm ² · day.

[0006]

In order to further improve the gas barrier properties of the deposited aluminum oxide film,
A method of generating oxygen plasma between an aluminum evaporation source and a deposition drum using a pressure gradient plasma gun has been adopted. Thereby, by promoting the reaction between aluminum and oxygen, it is possible to reduce the amount of supplied oxygen and prevent excess oxygen from being mixed into the film and becoming a defect,
Further, it is expected that oxygen gas and aluminum vapor are excited and diffused on the film surface to obtain a dense vapor-deposited film. One example of this manufacturing apparatus is shown in FIG. 5, and reference numeral 21 in the figure is the pressure gradient plasma gun.

However, the apparatus for producing aluminum oxide using the plasma gun 21 performs discharge for transporting electrons between the plasma gun 21 and the anode 16 (see FIG. 5). There was a disadvantage that aluminum oxide as an insulator adhered and the discharge became unstable. Therefore, in this case, continuous operation for three hours or more cannot be performed, and mass production is difficult, which has been a factor that increases the price of the aluminum oxide vapor-deposited film.

The present invention has been made in view of the above circumstances, and an object of the present invention is to manufacture a film for food packaging having excellent properties at low cost and in large quantities. It is to provide a device.

[0009]

The present invention employs the following means in order to solve the above-mentioned problems. That is, the film manufacturing apparatus according to claim 1 melts the material in order to perform a material vapor deposition process on a film transport system including a plurality of rolls including a vapor deposition roll and a film on the vapor deposition roll. An evaporation source to evaporate, oxygen supply means for supplying oxygen gas to a space between the evaporation roll and the evaporation source, and plasma generation for converting the oxygen gas into a plasma state by introducing microwaves into the space. Means.

According to this, when a substance is deposited on a film, oxygen gas is supplied to a space between the film and the evaporation source, and the oxygen gas is converted into a plasma state by microwaves. It will be. Therefore, a deposited film of an oxide related to the substance is formed on the film. In addition, unlike the principle of generating a discharge by electron transport of a plasma gun, which has been conventionally used, the plasma generating means uses a microwave to generate a discharge by generating an electron vibration in the space. Is obtained.

Further, the film manufacturing apparatus according to the present invention is characterized in that the substance is aluminum and the supply amount of the oxygen gas is set to 1.0 to 1.2 times the oxidation equivalent of the aluminum.

According to this, the deposited film formed on the film becomes aluminum oxide. Further, by setting the supply amount of the oxygen gas to be 1.0 to 1.2 times the oxidation equivalent of aluminum, it is possible to ensure the transparency of the manufactured aluminum oxide vapor-deposited film.

Further, in the film manufacturing apparatus according to a third aspect, the plasma generating means is connected to the microwave oscillator oscillating the microwave by a waveguide and is connected to the microwave oscillator around a longitudinal center thereof. A focusing coil capable of generating a magnetic field.

According to this, the microwave discharge plasma is confined by the magnetic field generated by the focusing coil. If the magnetic flux density is set to a value higher than the value at which electrons undergo cyclotron resonance by microwaves,
It is presumed that it is possible to increase the density of the plasma.

In addition, the film manufacturing apparatus according to a fourth aspect is characterized in that a high frequency voltage is applied to the vapor deposition roll.

According to this, the electrons and ions in the oxygen gas plasma are energized by the high-frequency voltage applied to the deposition roll. Therefore, an effect of bringing various particles to be deposited into a high energy state is produced.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram showing a configuration of a food packaging film manufacturing apparatus (hereinafter abbreviated as a film manufacturing apparatus). As can be seen from the figure, the film manufacturing apparatus in the present embodiment is of a continuous type.

The payout roll 1 stores a plastic film (film) 2 to be vapor-deposited in a reel shape. The plastic film 2 unwound from the payout roll 1 includes a plurality of seal rolls 3.
And is introduced into the vacuum chamber 4. Then, the plastic film 2 is deposited on a deposition roll 5 installed in a vacuum chamber 4.
, The aluminum oxide film is deposited on the plastic film 2 on the deposition roll 5. This will be described in detail later. The vapor-deposited film 8 on which aluminum oxide is vapor-deposited is discharged from the vacuum chamber 4, passes through the seal roll 3 again, and reaches the winding roll 9.

The payout roll 1, the seal roll 3, and the take-up roll 9 are installed on the apparatus pedestal D. Further, the seal roll 3 has a plurality of rolls arranged vertically in a tower form, and is provided to keep the inside of the vacuum tank 4 in a vacuum atmosphere. The vacuum chamber 4 is disposed below the seal roll 3 assembled in a tower shape and below the apparatus base D.

Further, a temperature control mechanism and a power supply for applying a high-frequency voltage are connected to the evaporation roll 5 respectively. These are not shown in FIG. The surface of the vapor deposition roll 5 is maintained at an appropriate temperature by the cooling mechanism and, when a high-frequency voltage is applied, acts to give energy to electrons and ions in oxygen plasma described later.

Further, between each of the rolls 1, 3, 5, and 9,
A plurality of tension rolls are arranged to apply an appropriate tension to the plastic film 2 or the vapor deposition film 8. In addition, as explained here,
The payout roll 1, the seal roll 3, the vapor deposition roll 5, and the take-up roll 9 constitute a film transport system of the film manufacturing apparatus in the present embodiment.

A suitable evacuation pump system is connected to the vacuum chamber 4 so that the inside thereof can be set to a desired degree of vacuum. The evacuation pump system is, for example, a rotary pump, a diffusion pump,
Alternatively, they are configured as a combination thereof, but the present invention does not particularly limit the configuration of the evacuation pump system.

In the vacuum chamber 4, an induction heating type crucible (evaporation source, hereinafter abbreviated as crucible) 6 is provided. In the present embodiment, aluminum (substance) is supplied therein. The crucible 6 is a kind of “container” for evaporating the aluminum. In addition, the aluminum is heated by an induction heating method using a high frequency so that the aluminum is melted and evaporated.
The aluminum thus evaporated passes through the vacuum atmosphere and reaches the top of the vapor deposition roll 5, and the vapor deposition is performed on the plastic film 2 passing therethrough.

In the vacuum chamber 4, two sets of oxygen gas nozzles (oxygen supply means) 10 are provided above the crucible 6. This is to supply oxygen gas between the vapor deposition roll 5 and the crucible 6, and serves as a supply source for supplying oxygen gas necessary for converting aluminum evaporated from the crucible 6 into aluminum oxide. The oxygen gas nozzle 10 is provided with a flow meter (not shown) so that the supplied oxygen amount can be confirmed and adjusted.

Inside and outside the vacuum chamber 4, there are provided plasma generating means for sending microwaves to the space between the vapor deposition roll 5 and the crucible 6. The plasma generating means is generally constituted by a microwave oscillator 12, a microwave inlet 11, a focusing coil 15, and an anode 16.

The microwave oscillator 12 is arranged outside the vacuum chamber 4, and the microwave oscillated therefrom passes through a power monitor 13 and a stub tuner 14 connected by a waveguide. The microwave is then applied to the vacuum chamber 4
Vacuum chamber 4 through microwave inlet 11 provided on the wall
Introduced within. The microwave inlet 11 has a focusing coil 15 capable of generating a magnetic flux density of about 900 Gauss.
Is provided. The microwave introduced into the vacuum chamber 4 causes the oxygen gas molecules supplied from the oxygen gas nozzle 10 described above to be ionized and causes the plasma state to appear. This plasma is confined by the magnetic field generated by the focusing coil 15.

An anode 16 is provided in the vacuum chamber 4. In this embodiment, the anode 1
As 6, the permanent magnet was applied to it. A probe meter (not shown) for setting plasma conditions is further provided in the vacuum chamber 4.

In the apparatus having the above structure, the production of the aluminum oxide vapor-deposited film is performed as follows. That is, the plastic film 2 passed through the payout roll 1 and the seal roll 3 and introduced into the vacuum chamber 4 reaches the vapor deposition roll 5. On the other hand, in the crucible 6, the aluminum supplied into the crucible 6 is melted and evaporated by induction heating. In the space between the crucible 6 and the deposition drum 5, the oxygen gas nozzle 10
With the supply of oxygen gas by the action of the microwaves introduced by the plasma generating means,
The supplied oxygen molecules are ionized into a plasma state. The aluminum evaporated from the crucible 6 reacts with this oxygen plasma. As a result, aluminum oxide is deposited on the plastic film 2. Since a power supply for applying a high-frequency voltage is connected to the evaporation roll 5, energy is given to electrons or ions in a plasma state. Therefore, vapor deposition with particles in a high energy state is performed on the plasma film 2. In this way, the deposited film 8 on which the aluminum oxide has been deposited passes through the seal roll 3 and is finally stored in the take-up roll 9 to be a completed product.

The production of the above-mentioned aluminum oxide vapor-deposited film is affected by various conditions such as the setting of plasma conditions, the degree of vacuum in the vacuum chamber 4 and the transport speed of the film. Therefore, these various conditions have a great effect on the properties of the deposited aluminum oxide deposited film, such as denseness, transparency, gas barrier properties (gas permeability), and the like. In the following, a description will be given of the knowledge obtained by preparing an aluminum oxide vapor-deposited film under various conditions, the performance test result of the vapor-deposited film, and the like.

In this embodiment, an aluminum oxide deposited film was produced under the conditions shown in Table 1. Table 2 shows the results of a probe measurement of the relationship between the plasma density, the pressure in the vacuum chamber 4 in Table 1, and the magnetic flux density in the focusing coil 15 in advance.

[0031]

[Table 1]

[0032]

[Table 2]

According to Table 2, it is understood that the plasma density increases when the magnetic flux density is 850 Gauss or more. This means that the microwave frequency in this embodiment is 2.45 GHz.
Is consistent with a magnetic flux density of 845 Gauss at which electrons undergo cyclotron resonance. From this result, it was found that the plasma density could be increased by applying a higher magnetic field. It is understood from Table 2 that the lower the vacuum in the vacuum chamber 4 is, the higher the plasma density is.

Next, under various conditions, an aluminum oxide vapor-deposited film was prepared, and its transparency and oxygen permeability were evaluated. The results are shown in Table 3. It should be noted that “conventional Al” in Table 3 indicates that only aluminum was vapor-deposited on the plastic film 2 without supplying oxygen gas from the oxygen gas nozzle 10.

[0035]

[Table 3]

From Table 3, it can be seen that transparency is secured after Test No. 2. Therefore, in order to obtain the transparency of the vapor-deposited film, the supply amount of oxygen may be set to 0.9 times or more of the oxidation equivalent of aluminum. More preferably, the value should be about 1.0 to 1.2 times. Regarding the oxygen permeability, if the acceptance criterion is 3 cc / cm ² · day,
As can be seen from Test Nos. 3 to 8 and the like in Table 3, an aluminum oxide vapor-deposited film having an oxygen permeability satisfying the acceptance criteria in a state where the pressure in the vacuum chamber 4 is set to a vacuum lower than 1.2 × 10 ⁻³ Torr Could be obtained. Also, from the comparison of test number 11 in Table 3 with other data, the plasma density was 1.
Under a magnetic flux density condition of 0 × 10 ¹⁷ m ⁻³ or more (a magnetic flux density of the focusing coil of 850 Gauss or more, see Table 2), a vapor deposition film satisfying the acceptance criteria was similarly obtained. Further, from comparison between Test Nos. 13 and 14 and other data, it was possible to obtain a vapor-deposited film having a low oxygen permeability by applying a high-frequency voltage to the vapor-deposition roll 5.

Further, using the above film deposition apparatus, 1
A 0 hour continuous aluminum oxide deposited film production test was performed. The manufacturing conditions were based on Test No. 3 in Table 2. The aluminum oxide vapor-deposited film produced in the 10-hour continuous test was taken from the take-up roll 9 every other hour, and its transparency and oxygen permeability were evaluated. The degree was confirmed to be between 2.1 and 2.3. That is, it was confirmed that the film deposition apparatus of the present embodiment can continuously manufacture high-quality products for a long time.

As described above, according to the film deposition apparatus of the present embodiment, an aluminum oxide deposited film having excellent properties such as transparency and high gas barrier properties can be produced stably, inexpensively and in large quantities. Can be. This is because, unlike a deposition apparatus using a conventional “plasma gun”, there is no disadvantage that the discharge becomes unstable even if aluminum oxide is deposited on the anode. More specifically, conventionally, plasma was generated by discharge due to electron transport between the plasma gun and the anode, whereas in the present embodiment, microwave discharge was used as a principle, that is, by oscillating electrons in space. This is because, since the plasma is generated, even if aluminum oxide is vapor-deposited on the anode 16, the discharge form is not changed and does not become unstable. This is a major factor in that the present device can realize stable operation for a long time.

Further, by applying a high-frequency voltage on the deposition roll 5, electrons and ions in the plasma are accelerated by the high-frequency voltage, so that high-energy particles can be deposited on the plastic film 2. It becomes possible. As a result, the surface diffusion movement becomes more active, and the film can be made denser. In other words, a good film having a high gas barrier property can be manufactured as the completed vapor deposition film.

The present invention is not particularly limited with respect to the specific form of the film manufacturing apparatus shown in the above embodiment. That is, in the above, the type is a continuous type. However, in some cases, a plasma including the microwave oscillator 12 as a component is provided to a batch type film manufacturing apparatus as described in the section of the related art. It may be a form provided with a generating means. In short, any vapor deposition film manufacturing system using microwave discharge plasma can be interpreted as being within the scope of the present invention.

Further, in connection with the above, in the present embodiment, the crucible 6 of the induction heating type is used as the evaporation source, but the present invention is not limited to this. For example, a device using an electron beam as a heating source is also included in the concept of the present invention.

[0042]

As described above, the film producing apparatus according to the first aspect of the present invention is conventionally used because the plasma generating means for converting the oxygen gas into a plasma state by introducing microwaves is roughly hand-cast. Unlike the principle of discharge by electron transport in a plasma gun, discharge is obtained by generating vibrations of electrons, so that stable operation can be performed for a long time. This also enables mass production of films produced using plasma, and can set the market price at a low price.

In the film manufacturing apparatus according to the present invention, the aluminum gas is evaporated and the supply amount of the oxygen gas is set to be 1.0 to 1.2 times the oxidation equivalent of the aluminum. Transparency, which is one of the properties, can be secured.

Further, in the film manufacturing apparatus according to the third aspect, the plasma generated by the microwave can be confined by a magnetic field. Then, for example, when the setting of this magnetic field is set to a value equal to or higher than the value at which electrons undergo cyclotron resonance, it is possible to increase the density of the plasma. This has been described in the above embodiment.

In addition, in the film manufacturing apparatus according to the fourth aspect, by applying a high-frequency voltage to the vapor deposition roll, energy is given to electrons and ions in the plasma, so that various types of vapor deposition are performed. It is possible to bring the particles into a high energy state. Therefore, the diffusion movement in the film at the time of vapor deposition becomes more active, and the denseness of the deposited film to be formed is increased, so that a film having high gas barrier properties can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a film manufacturing apparatus according to an embodiment.

FIG. 2 is an explanatory diagram showing a configuration of a conventional continuous film manufacturing apparatus.

FIG. 3 is an explanatory view showing a configuration of a conventional batch type film manufacturing apparatus.

FIG. 4 is an explanatory view showing a configuration of a film manufacturing apparatus provided with a conventional plasma generating means.

[Explanation of symbols]

 2 plastic film (film) 5 evaporation roll 6 crucible (evaporation source) 10 oxygen gas nozzle 12 microwave oscillator 15 focusing coil

Claims (4)

[Claims] 1. A film transport system comprising a plurality of rolls including a vapor deposition roll, and an evaporation source for melting and evaporating the substance in order to perform a substance vapor deposition process on a film on the vapor deposition roll; An oxygen supply unit that supplies oxygen gas to a space between the evaporation roll and the evaporation source, and a plasma generation unit that brings the oxygen gas into a plasma state by introducing microwaves into the space. A film manufacturing apparatus characterized by the above-mentioned. 2. The method according to claim 1, wherein the substance is aluminum, and the supply amount of the oxygen gas is 1.0 to 1.2 times the oxidation equivalent of the aluminum.
2. The film manufacturing apparatus according to claim 1, wherein the setting is twice. 3. The plasma generating means includes: a microwave oscillator for oscillating the microwave; and a focusing coil connected to the microwave oscillator by a waveguide and capable of generating a magnetic field around a center in a longitudinal direction of the microwave oscillator. The film manufacturing apparatus according to claim 1, wherein: 4. The film manufacturing apparatus according to claim 1, wherein a high-frequency voltage is applied to the deposition roll.