JP2002234521A - Method for forming film on wall surface of plastic container, film forming device, and plastic container - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for forming a uniform film on a wall surface of (in particular, an inner wall surface) of a container irrespective of a shape or a size of a plastic container. SOLUTION: An outer electrode 26 is stored in a reactor 10, a plastic container 30 is stored in a space of the outer electrode 26, a space of the outer electrode 26 is made vacuum under a state in which an inner electrode 21 is stored in a container 30. When a high frequency electrical power is fed to the outer electrode 26 while raw material gas of a silicon oxide film is being fed into the container 30, the raw material gas is changed into plasma and a silicon oxide film is formed at a wall surface of the container 30. Since the outer electrode 26 is freely loaded into or unloaded out of the reactor 10, it is possible to use the outer electrode 26 formed with a space while it is being aligned with the outer shape of the container 30.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a coating film on a wall surface of a plastic container and an apparatus therefor.

[0002]

2. Description of the Related Art Plastic containers are widely used as food and drink or pharmaceutical containers because of their ease of molding, light weight, low cost, and the like. That is not to say. For example, plastic has a property of transmitting low molecular gas such as oxygen and carbon dioxide. For this reason, for example, when a beverage is filled into a plastic container, there is a problem that the beverage is oxidized by oxygen entering through the plastic container and the quality is deteriorated. Further, if the beverage is a carbonated beverage, the carbon dioxide dissolved in the beverage passes through the plastic container and scatters to the outside, and the quality is reduced. Also,
Another problem is caused by the sorption (absorption and fixation inside) of the low molecular weight organic compound by the plastic. That is, when a considerable time elapses between the use of the plastic container and the collection thereof, the low-molecular-weight organic compound such as a mold component is sorbed to the container. And the substance thus sorbed in the plastic container is not removed by ordinary washing. This is one of the factors that hinders the use of plastic containers as returnable containers.

The invention made in view of the above problem is disclosed in Japanese Patent Application Laid-Open
No. 53117. The invention described in the publication relates to a method for applying a carbon film coating on the inner wall surface of a plastic container and an apparatus therefor. In the film forming process according to the present invention, electrodes are arranged inside and outside the plastic container, the inside of the container is evacuated, a raw material gas is supplied thereto, and high-frequency power is supplied to the external electrodes. Thereby, the raw material gas in the container is turned into plasma, and a carbon film is formed on the inner wall surface. If the inner wall surface of the plastic container is coated with the carbon film as described above, oxygen, carbon dioxide, water vapor, and the like cannot pass through the plastic container, so that the quality of the content is prevented from being deteriorated. In addition, since the carbon film coating prevents the contents from being sorbed on the container wall, the plastic container can be used as a returnable container.

[0004] An improved invention of the invention described in JP-A-8-53117 is disclosed in JP-A-2000-230064. The film forming apparatus described in the publication, the plastic outer cylinder according to the shape and size of the container is arranged between the external electrode and the container, thereby,
It is stated that a very high degree of vacuum due to the gap between the external electrode and the container can be easily maintained without replacing the external electrode.

[0005]

When a film is formed on the wall surface of a plastic container by plasma processing, it is preferable to make the distance from the electrode to the wall surface almost constant in order to make the film thickness uniform (Japanese Unexamined Patent Publication No. Hei 8- No. 53117, paragraph [0]
024], [0027]). However, JP 200
Since the film forming apparatus described in Japanese Patent Application Publication No. 0-230064 is intended to accommodate containers of various shapes and sizes without changing the set of electrodes, the distance from the electrode to the wall surface of a certain container is almost constant. However, this is not the case for another container, and the film formation is not uniform. The present invention has been made to solve such a problem, and an object of the present invention is to form a film uniformly on the wall surface of a plastic container regardless of the shape and size of the container. An object of the present invention is to provide a membrane method and an apparatus therefor.

[0006]

A method for forming a film on a wall surface of a plastic container according to the present invention, which has been made to solve the above-mentioned problems, has a space for accommodating a plastic container having a predetermined shape and size. An external electrode having a space whose wall surface is substantially the same shape as the wall surface of the plastic container, a reactor for accommodating the external electrode in an insulated state, and a film forming method using a grounded internal electrode. The plastic container so that the external electrode is housed in the reactor, the plastic container is housed in the space of the external electrode, and the internal electrode is inserted into the mouth of the plastic container. The procedure of arranging the external electrode and the internal electrode inside the reactor, and evacuating the space of the external electrode housed in the reactor,
The method may further include supplying a raw material gas for the silicon oxide film into the plastic container accommodated in the space, and supplying high frequency power to the external electrode.

The apparatus for forming a film on a wall surface of a plastic container according to the present invention is a space for accommodating a plastic container having a predetermined shape and size, and the wall surface has substantially the same shape as the wall surface of the plastic container. An external electrode having a space that is a reactor for accommodating the external electrode in an insulated state, when the external electrode is accommodated in the reactor, and when the plastic container is accommodated in the external electrode, the plastic A grounded internal electrode inserted into the mouth of the container, an exhaust unit for exhausting the inside of the reactor, the external electrode is housed in the reactor, and the plastic container is housed in the space of the external electrode. And the source gas supply means for supplying the source gas of the silicon oxide film to the inside of the plastic container, Characterized in that it comprises a power-on means for turning on the RF power to Kigaibu electrode.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The method according to the present invention is a type of method for forming a film on the wall surface of a plastic container by plasma processing using high-frequency power. In such a method, by using an external electrode having a space corresponding to the size and shape of the container to be treated, a film can be uniformly formed on the wall surface of the container having any size and shape. it can. For example, when the container is used particularly for storing beverages, as described in paragraph [0015] of JP-A-8-53117, the inner wall surface of the container is mainly subjected to film formation. In such a case, the inner wall shape of the space of the outer electrode may be substantially the same as the inner wall shape of the container.

In the present invention, a reactor for accommodating an external electrode is prepared, and the external electrode is attached to the apparatus via the reactor. The effects obtained by such a configuration are as follows.

First, if the mounting structure of the external electrodes to the apparatus is complicated, the work of replacing the external electrodes according to the container becomes troublesome. However, when the above-mentioned reactor is used, a structure in which an external electrode is made detachable from the reactor by, for example, filling can be easily realized. In plasma processing, a high vacuum is required.
In the device disclosed in Japanese Patent Application Laid-Open No. 7-107, a space (vacant space in the same application) formed by combining a plurality of components of the external electrode also functions as a plasma processing chamber. Therefore, when preparing a plurality of external electrodes according to the shape of the container, high airtightness between members must be achieved in all the external electrodes. On the other hand, in the present invention, if high airtightness between members is achieved in the reactor, it is not necessary to consider such airtightness for each external electrode, and various external electrodes can be produced at low cost. can do.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A film forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a plan view of a film forming apparatus of the present embodiment and a cross-sectional view taken along line II of the plan view. Although the part shown in FIG. 1 is housed in the casing, it is not shown. Some of the components shown in the cross-sectional views are omitted in the plan views.

The film forming apparatus of the present embodiment includes a reactor 10 composed of a first reactor member 11 and a second reactor member 12 made of a conductor. The first reactor member 11 is attached to a base plate 14 via a first reactor support 13. An insulating member 131 made of Teflon (trademark) is used for the first reactor support 13, and thereby the first reactor member 11 is insulated from the base plate 14. An O-ring 132 is provided at a contact portion of the first reactor member 11 with the second reactor member 12. On the other hand, the second reactor member 12 is attached to a second reactor support 16 mounted on a guide rail 18 (fixed to the base plate 14) by a pedestal 161. The insulating member 162 is also used for the second reactor support 16, so that the second reactor member 12 is insulated from the guide rail 18 and the base plate 14.

A supply / exhaust port 113 is provided on one side surface of the first reactor member 11, and a supply / exhaust unit 20 is attached to this port. The supply / exhaust unit 20 includes the reactor 1
It has an exhaust pipe 201 for removing air from 0 and a gas manifold 21 for supplying a raw material gas of the silicon oxide film to the inside of the reactor 10. The exhaust pipe 201 is connected to a vacuum pump (not shown), and the gas manifold 21 is connected to a source gas supply source (not shown). The gas manifold 21 is made of a conductor, and also functions as a grounded internal electrode according to the present invention. Air supply and exhaust unit 2
The first reactor member 11 is insulated from the supply / exhaust unit 20 by the use of an insulating member 203. A high-frequency power supply 24 for supplying high-frequency power to the first reactor member 11 through the RF copper plate 241 is disposed below the base plate 14.

A first reactor member 11 and a second reactor member 12
A bottomed cylindrical external electrode 26 is accommodated in the reactor 10 formed by combining the above. The external electrode 26 is formed by combining a first electrode member 27 housed in the first reactor member 11 and a second electrode member 28 housed in the second reactor member 12. First electrode member 27 and second electrode member 2
8 are formed with holes 271 and 281 respectively.
When the first electrode member 27 and the second electrode member 28 are combined as shown in FIG. 1, these holes 271 and 281
Forms a space for accommodating the plastic container 30 (hereinafter, referred to as the container 30). The inner wall surface of this space is formed in substantially the same shape as the wall surface of the container 30, and the outer wall surface at the tip of the gas manifold 21 described above is also formed according to the wall shape of the container 30. The hole 271 of the first electrode member 27 penetrates the electrode 27 in the length direction (the insertion direction of the container 30). On the other hand, a hole 281 of the second electrode member 28 has a bottom, in which a spacer member 282 made of a conductor is loaded.

External electrode 26 and vessel 30 to reactor 10
Will be described with reference to FIG. First, the first electrode member 27 and the second electrode member 28 are accommodated in the first reactor member 11 and the second reactor member 12, respectively (FIG. 2A). The first electrode member 27 is connected to the first reactor member 1
1, the hole 271 of the first electrode member 27 is connected to the supply / exhaust port 113 of the first reactor member 11, and the gas manifold 21 is inserted into the hole 271 (FIG. 2).
(B)). Next, the container 30 is housed in the hole 271 of the first electrode member 27 while inserting the gas manifold 21 into the mouth. Then, the second reactor support 16 is connected to the guide rail 1.
2 along the left side of FIG.
2 is brought into close contact with the first reactor member 11, and the two are joined by the locking member 29.

As a result of the above operations, as shown in FIG. 1, the external electrode 26 is accommodated in the reactor 10, the container 30 is accommodated in the space of the external electrode 26, and the gas manifold (internal electrode) 21 is accommodated. Is inserted into the container 30. In this state, the external electrodes 2 are
The space 6 is evacuated, and a raw material gas for the silicon oxide film is supplied from a gas supply source (not shown) into the container 30 through the gas manifold 21. The source gas is, for example, TEOS (Te
traethoxy Silane), TMOS (Tetramethoxy Silan)
e) A mixed gas containing an organic silicon compound containing a silicon alkoxide system such as e) and oxygen. When the high-frequency power supply 24 is activated together with the supply of the raw material gas, the high-frequency power is supplied to the external electrode 26 through the RF steel plate 241 and the reactor 10 (made of a conductor), and the raw material gas in the container 30 is grounded. Plasma is generated between the internal electrode 21 and the external electrode 26. Here, the external electrode 26 is the internal electrode 2
Although it has a surface area larger than 1, the potential of the plasma is always higher than the potential of the external electrode 26, so that the potential difference accelerates the positive ions in the plasma toward the inner wall of the container 30 along the wall surface of the external electrode 26. The collision occurs, and a silicon oxide film is formed there.

In this embodiment, since the reactor 10 is made of a conductor, not only the external electrode 26 but also the entirety of the reactor 10 and the external electrode 26 function as an external electrode paired with the internal electrode 21. However, it is not essential for the present invention that the reactor 10 is made of a conductor. For example, the RF copper plate 241 and the first electrode member 27 are provided on the bottom of the first reactor member 11.
May be provided with a conductive member for electrically connecting.

In the apparatus of the present embodiment, the external electrode 26 and the container 30 are arranged substantially horizontally (horizontally) inside the reactor 10. With this arrangement, it is easier to put the external electrode 26 and the container 30 into and out of the reactor 10 than to arrange the external electrode 26 and the container 30 substantially vertically (long vertically). Further, since the constituent members 27 and 28 of the external electrode 26 are heavy, it is advantageous to reduce the amount of movement in the vertical direction by horizontal arrangement. In the apparatus of the present embodiment, the reactor 1
0 is the component 2 of the external electrode 26.
7 and 28 are configured to be in close contact with each other at an oblique surface with respect to the insertion direction. In this case, since the openings of the constituent members 11 and 12 of the reactor 10 open greatly in the oblique direction, the constituent members 27 and 2 of the external electrode 26 to the reactor 10 are connected.
8 is easier to put in and out. Similarly, the external electrode 26
By making the constituent members 27 and 28 close to each other obliquely with respect to the insertion direction of the container 30, it is easier to put the container 30 in and out of the space of the external electrode 26.

In the above-described apparatus, the reactor 10 may generate high heat when high-frequency power is supplied. Assuming such a case, for example, if a cooling mechanism for flowing cooling water is provided to a pipe disposed on the outer surface of the reactor 10, processing can be performed even in a plastic container that is weak against high heat. Also,
If the outside of the reactor 10 is covered with a grounded conductive shield member to block high frequency and heat radiated to the outside, safety is enhanced. The conductive shield member need not be disposed in contact with the reactor 10;
The device may be in the shape of a case for housing the entire device shown in FIG.

[Brief description of the drawings]

FIG. 1 is a plan view of a film forming apparatus according to one embodiment of the present invention, and a cross-sectional view taken along line II of the plan view.

FIG. 2 is a diagram showing a procedure for housing an external electrode and a container in a reactor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Reactor 11 ... First reactor member 12 ... Second reactor member 14 ... Base plate 18 ... Guide rail 21 ... Gas manifold (internal electrode) 24 ... High frequency power supply 26 ... External electrode 27 ... First electrode member 28 ... Second electrode member 30: plastic container

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // C08L 101: 00 B65D 1/00 CB F term (reference) 3E033 AA02 BA13 BB08 CA16 DB01 DD02 3E062 AA09 AB02 AB14 AB20 AC02 JA07 JB22 JC04 JD01 4F006 AA11 AA31 AB76 BA05 BA11 CA07 DA01 4K030 AA06 AA09 BA44 CA07 CA15 KA14

Claims (3)

[Claims] 1. An external electrode having a space for accommodating a plastic container having a predetermined shape and size, wherein a wall surface of the external electrode has substantially the same shape as a wall surface of the plastic container. And a film forming method using a grounded internal electrode, wherein the external electrode is housed in the reactor, the plastic container is housed in the space of the external electrode, A procedure in which the plastic container, the external electrode and the internal electrode are arranged inside the reactor so that the electrode is inserted into the mouth of the plastic container, and the external device accommodated in the reactor The space of the electrode is evacuated, the raw material gas of the silicon oxide film is supplied to the inside of the plastic container housed in the space, and the high frequency power is supplied to the external electrode. Method for deposition onto the wall surface of the plastic container, characterized in that it comprises the steps. 2. An external electrode having a space for accommodating a plastic container having a predetermined shape and size, wherein an inner wall surface has a substantially same shape as an inner wall surface of the plastic container. A reactor for housing in an insulated state, wherein the external electrode is housed in the reactor, and when the plastic container is housed in the external electrode, inserted into the mouth of the plastic container, grounded Internal electrode, exhaust means for evacuating the inside of the reactor, when the external electrode is housed in the reactor, and the plastic container is housed in the space of the external electrode,
A source gas supply unit for supplying a source gas of the silicon oxide film to the inside of the plastic container, and a power input unit for inputting high-frequency power to the external electrode housed in the reactor are provided. A film forming apparatus on the wall surface of a plastic container. 3. A plastic container having a silicon oxide film formed on a wall surface by the method according to claim 1 or using the apparatus according to claim 2.