AU2005334309B2

AU2005334309B2 - Apparatus for forming a coating film on an inner surface of a container

Info

Publication number: AU2005334309B2
Application number: AU2005334309A
Authority: AU
Inventors: Yuji Asahara; Fumihiko Ishise; Masaaki Nakachi; Atsushi Ueda; Hideo Yamakoshi
Original assignee: Mitsubishi Heavy Industries Food and Packaging Machinery Co Ltd
Current assignee: Mitsubishi Heavy Industries Machinery Systems Co Ltd
Priority date: 2005-07-12
Filing date: 2005-07-12
Publication date: 2010-06-17
Anticipated expiration: 2025-07-12
Also published as: WO2007007395A1; AU2005334309B8; KR101029657B1; CN101223299A; AU2005334309A1; CN101223299B; KR20080019285A

Description

C:\RPotbl\DCC\1L\2932995_1 DOC-6W5/2010 -1 DESCRIPTION APPARATUS FOR FORMING A COATING FILM ON AN INNER SURFACE OF A CONTAINER 5 [0001] The present invention relates to an apparatus for forming a coating film on the inner surface of a container. [0002] It has been proposed to form a barrier film, for example, a carbon film such as a DLC (Diamond-Like Carbon) 10 on the inner surface of a plastic container such as a plastic bottle to prevent oxygen from permeating from the outside to the inside of the container and/or to prevent carbon dioxide from escaping from the contents of the container (for example, carbonated drinks) (Patent 15 Document 1). [0003] A method of forming a carbon film on the inner surface of such plastic container is disclosed in Patent Document 2 that has already been applied by the present applicant and published. In Fig. 7 of the Patent 20 Document 2, an apparatus for forming a carbon film on the inner surface of a plastic container is described. The carbon-film forming apparatus includes: an external electrode that is large enough to surround the plastic container when the plastic container that is an object to be 25 processed is inserted therein; a spacer made of a dielectric material that is interposed between at least the mouth and shoulder of the container and the external electrode when the plastic container is inserted in the external electrode; an 2 exhaust pipe mounted on an end surface of the external electrode on a side on which the mouth of the container is positioned via an insulating member; an internal electrode that is inserted in the plastic container of the external 5 electrode from a side of the exhaust pipe and that is connected to a ground side; an exhaust unit mounted on the exhaust pipe; a gas supplying unit that supplies a medium gas to the internal electrode; and a high-frequency power source connected to the external electrode. 10 [0004] A method of forming a carbon film on the inner surface of the plastic container such as a plastic bottle by the carbon-film forming apparatus disclosed in the Patent Document 2 with such configuration is explained below. 15 [0005] First, a plastic bottle is inserted in the external electrode. The internal electrode provided with a gas outlet portion made of an insulating material is inserted inside the plastic bottle from the exhaust pipe arranged via the insulating member on the end surface of 20 the external electrode on a side on which the mouth of the plastic bottle is positioned so that the gas outlet portion is positioned on a bottom side of the plastic bottle. After gas inside and outside the plastic bottle is discharged through the exhaust pipe by the exhaust unit, a 25 medium gas is supplied to the internal electrode from the gas supplying unit and is blown out of the gas outlet portion of the internal electrode into the plastic bottle to set gas pressure inside the plastic bottle and the exhaust pipe to a predetermined value. High-frequency 30 electric power from the high-frequency power source is supplied to the external electrode to generate plasma around the internal electrode in the plastic bottle. The plasma causes the medium gas to dissociate and a carbon C:\NRPonbflDCC\L\2932995 1 DOC-6S12010 -3 film to be formed on the inner surface of the plastic bottle. At this time, a discharge area can be extended not only around the internal electrode but also in the exhaust pipe (including a branch exhaust pipe communicated 5 therewith). [00061 However, when a plurality of film-forming chambers that have an external electrode and an exhaust pipe are each connected to a rotary vacuum sealing mechanism serving as an exhaust unit through the exhaust pipes (branch exhaust pipe) 10 in the carbon-film forming apparatus having the above configuration, the discharge area reaches the rotary vacuum sealing mechanism through the exhaust pipe. In addition, discharge from a film-forming chamber interferes with discharge (plasma) that reaches the rotary vacuum sealing 15 mechanism from an adjacent film-forming chamber, which possibly causes instability of discharge and a power source failure. When the discharge area spreads into the exhaust pipe, power inside the plastic bottle may decrease, leading to a 20 decrease of power efficiency. Therefore, the present inventors have been engaged in research and development to restrict the discharge area to a neighborhood of the internal electrode in the plastic bottle as much as possible. 25 [0007] Patent Document 1: Japanese Patent Application Laid-open No. H8-53116 Patent Document 2: Japanese Patent Application Laid-open No. 2003-286571 [0008] The present inventors have been dedicated to the 30 research about a barrier-film forming apparatus in which a plurality of film-forming chambers used to form a barrier C:NRPorbIl\DCCUL\2932995_1 DOC.64)5/2010 -4 film on the inner surface of a plastic container as an object to be processed are communicated through exhaust pipes made of a conductive material with a rotary vacuum sealing mechanism and a method of forming a barrier film 5 such as a carbon film on the inner surface of the plastic container by using the barrier-film forming apparatus. Consequently, the present inventors have found that, by extending a discharge area from the film-forming chamber to the exhaust pipe, contrary to their expectation, a large 10 plasma sheath voltage is applied between an external electrode and a ground electrode including the film-forming chamber and the exhaust pipe. This enables the inner surface of the plastic container to be irradiated with positive ions with high energy generated from a barrier-film 15 forming gas such as a medium gas that dissociates in the plasma. Thus, on the inner surface of the plastic container can be formed a barrier film such as a carbon film that has a good film quality at high speed. However, as explained in the background art, extension of the discharge area from the 20 film-forming chamber to the exhaust pipe causes instability of discharge and a power source failure due to a relation with the rotary vacuum sealing mechanism. [0009] According to the present invention, there is provided an apparatus for forming a coating film on an inner 25 surface of a container, comprising: a film-forming chamber for forming a coating film by plasma discharge on an inner surface of a container to be processed, wherein the film forming chamber includes an external electrode that has a hollow large enough to surround the container when the 30 container is inserted therein; a conductive chamber head that is arranged through an insulating member on an end surface of the external electrode on a side on which a mouth C:\NRPortbl\DCC\L\2932995_I.DOC-6A)5/2010 -5 of the container is positioned, that is connected to an exhaust pipe, and that is grounded; a gas outlet that is inserted in the container in the external electrode from a side of the chamber head, and that discharges film-forming 5 gas; and an electric-field applying unit that applies an electric field between the external electrode and the chamber head and the exhaust pipe that are grounded, wherein the exhaust pipe is made of a conductive material, inside which an electric-field shielding member having air 10 permeability and a conductive property is arranged at a position a desired distance away from the film-forming chamber, and the desired distance is set such that an area ratio (S2/Sl) between an area Sl of an inner surface of the external electrode in which the container is housed and an 15 area S2 of the ground electrode constituted by the chamber head, the exhaust pipe made of the conductive material, and the electric-field shielding member, is equal to or more than one. [0010] Preferred embodiments of the present invention 20 provide a coating-film forming apparatus for forming a coating film on the inner surface of a container capable of preventing instability of discharge and an electric power failure by preventing a discharge area generated in an exhaust pipe from reaching a rotary vacuum sealing 25 mechanism. [0011] By arranging an electric-field shielding member having air permeability and conductive properties at a desired position inside an exhaust pipe made of a conductive material, it is possible to control a discharge area 30 generated in the exhaust pipe not to reach a rotary vacuum sealing mechanism, which prevents instability of discharge and a power source failure.

C:NRPotb\DCCUL2932995 1. DOC.6M5/2010 -6 [0012] In accordance with preferred embodiments of the invention, instead of arranging the electric-field shielding member in the exhaust pipe, the exhaust pipe includes a portion made of a conductive material and a portion made of 5 an insulating material, and the portion made of a conductive material is connected to the film-forming chamber. With this, it is also possible to control a discharge area generated in the exhaust pipe not to reach the rotary vacuum sealing mechanism, which prevents instability of discharge 10 and a power source failure. [0013] According to an embodiment of the present invention, a coating-film forming apparatus includes a rotary vacuum sealing mechanism; and a plurality of film forming chambers for forming a coating film by plasma 15 discharge on an inner surface of a container to be processed and that communicate with the rotary vacuum sealing mechanism through an exhaust pipe, the exhaust pipe being made of a conductive material, inside which an electric field shielding member having air permeability and a 20 conductive property is arranged at a position a desired distance away from the film-forming chamber. [0014] According to an embodiment of the present invention, a coating-film forming apparatus includes a rotary vacuum sealing mechanism; and a plurality of film 25 forming chambers for forming a coating film by plasma discharge on an inner surface of a container to be processed and that communicate with the rotary vacuum sealing mechanism through an exhaust pipe, the exhaust pipe being made of a conductive material, inside which an electric 30 field shielding member having air permeability and a conductive property is arranged at a position a desired distance away from the film-forming chamber, the electric- C:PonblDCCUlL\2932 5- 1. DOC4w5/O10 -7 field shielding member having any one of a honeycomb structure and a mesh structure. [0015] According to an embodiment of the present invention, the film-forming chamber includes an external 5 electrode that has a hollow large enough to surround the container when the container is inserted therein; a conductive chamber head that is arranged through an insulating member on an end surface of the external electrode on a side on which a mouth of the container is 10 positioned, that is connected to the exhaust pipe, and that is grounded; a gas outlet that is inserted in the container in the external electrode from a side of the chamber head and that discharges film-forming gas; and an electric-field applying unit that applies an electric field between the 15 external electrode and the chamber head and the exhaust pipe that are grounded. [0016] According to an embodiment of the present invention, the film-forming chamber includes an external electrode that has a hollow large enough to surround the 20 container when the container is inserted therein; a conductive chamber head that is arranged through an insulating member on an end surface of the external electrode on a side on which a mouth of the container is positioned, that is connected to the exhaust pipe, and that 25 is grounded; a gas outlet that is inserted in the container in the external electrode from a side of the chamber head and that discharges film-forming gas; and an electric-field applying unit that applies an electric field between the external electrode and the chamber head and the exhaust pipe 30 that are grounded, and a spacer made of a dielectric material is interposed between at least the mouth and a shoulder of the container and the external electrode when C:\NRPfnblDCCVL\2932995-I.DOC-6A)5f2O10 -8 the container is inserted. [0017] The container may be a plastic container. [0018] Also disclosed herein is a method of producing a container having a coated inner surface by using a coating 5 film forming apparatus described above, which includes (a) a step of inserting a container to be processed in each external electrode of the plurality of film-forming chambers; (b) a step of inserting the gas outlet inside the container from the conductive chamber head that is arranged 10 through the insulating member on the end surface of the external electrode on the side on which the mouth of the container is positioned; (c) a step of setting gas pressure inside the container, the chamber head, and the exhaust pipe to a predetermined value while gas inside and outside the 15 container and the chamber head is discharged by the rotary vacuum sealing mechanism through the exhaust pipe inside which the electric-field shielding member having air permeability and a conductive property is arranged at a desired position, and film-forming gas is discharged from 20 the gas outlet into the container; and (d) a step of forming a coating film on the inner surface of the container by applying an electric field between the external electrode and the chamber head and a ground electrode that includes part of the exhaust pipe corresponding to from the electric 25 field shielding member to the chamber head by the electric field applying unit, generating plasma in the container, the chamber head, and the part of the exhaust pipe, and dissociating the film-forming gas by the plasma. [0019] Also disclosed herein is a method of producing a 30 container having a coated inner surface by using a coating film forming apparatus described above, which includes (a) a step of inserting a container to be processed in each C:WRPortbl\CC\L\2932995 I DlOC-6h5/20 -9 external electrode of the plurality of film-forming chambers; (b) a step of inserting the gas outlet inside the container from the conductive chamber head that is arranged through the insulating member on the end surface of the 5 external electrode on the side on which the mouth of the container is positioned; (c) a step of setting gas pressure inside the container, the chamber head, and the exhaust pipe to a predetermined value while gas inside and outside the container and the chamber head is discharged by the rotary 10 vacuum sealing mechanism through the exhaust pipe inside which the electric-field shielding member having air permeability and a conductive property is arranged at a desired position , and film-forming gas is discharged from the gas outlet into the container; and (d) a step of forming 15 a coating film on the inner surface of the container by applying an electric field between the external electrode and the chamber head and a ground electrode that includes part of the exhaust pipe corresponding to from the electric field shielding member to the chamber head by the electric 20 field applying unit, generating plasma in the container, the chamber head, and the part of the exhaust pipe, and dissociating the film-forming gas by the plasma. When the container is inserted in the external electrode, a spacer made of a dielectric material is interposed between at least 25 the mouth and a shoulder of the container and the external electrode. [00201 According to an embodiment of the present invention, a coating-film forming apparatus includes a rotary vacuum sealing mechanism; and a plurality of film 30 forming chambers for forming a coating film on an inner surface of a container to be processed and that communicate with the rotary vacuum sealing mechanism through an exhaust C:\NRPortbr\DCCU Ll93295 LDOC-6AJ5/2010 -10 pipe, the exhaust pipe including a conductive pipe portion made of a conductive material and an insulating pipe portion made of an insulating material, the conductive pipe portion being connected to each of the film-forming chambers. 5 [0021] According to a ninth aspect of the present invention, a coating-film forming apparatus includes a rotary vacuum sealing mechanism; and a plurality of film forming chambers for forming a coating film on an inner surface of a container to be processed and that communicate 10 with the rotary vacuum sealing mechanism through an exhaust pipe, the exhaust pipe including a conductive pipe portion made of a conductive material and an insulating pipe portion made of an insulating material, the conductive pipe portion being connected to each of the film-forming chambers, the 15 film-forming chamber including an external electrode that has a hollow large enough to surround the container when the container is inserted therein; a conductive chamber head that is arranged through an insulating member on an end surface of the external electrode on a side on which a mouth 20 of the container is positioned, that is connected to the exhaust pipe, and that is grounded; a gas outlet that is inserted in the container in the external electrode from a side of the chamber head and that discharges film-forming gas; and an electric-field applying unit that applies an 25 electric field between the external electrode and the chamber head and the exhaust pipe that are grounded. [0022] When the container is inserted, a spacer made of a dielectric material may be interposed between at least the mouth and a shoulder of the container and the external 30 electrode. [0023] A method of producing a container having a coated inner surface by using a coating-film forming apparatus C:\NRPorblDCC\IL\2932995 1.DOC6M5/2010 -11 described above includes (a) a step of inserting a container to be processed in each external electrode of the plurality of film-forming chambers; (b) a step of inserting the gas outlet inside the container from the conductive chamber head 5 that is arranged through the insulating member on the end surface of the external electrode on the side on which the mouth of the container is positioned; (c) a step of setting gas pressure inside the plastic container, the chamber head, and the exhaust pipe to a predetermined value while gas 10 inside and outside the container and the chamber head is discharged by the rotary vacuum sealing mechanism through the exhaust pipe that includes a pipe portion made of a conductive material and a pipe portion made of an insulating material, and film-forming gas is discharged from the gas 15 outlet into the container; and (d) a step of forming a coating film on the inner surface of the container by applying an electric field between the external electrode and a ground electrode that includes the chamber head and the pipe portion made of a conductive material by the 20 electric-field applying unit, generating plasma in the container, the chamber head, and the pipe portion made of a conductive material, and dissociating the film-forming gas in the plasma. [0024] A method of producing a container having a coated 25 inner surface by using a coating-film forming apparatus described above includes (a) a step of inserting a container to be processed in each external electrode of the plurality of film-forming chambers; (b) a step of inserting the gas outlet inside the container from the conductive chamber head 30 that is arranged through the insulating member on the end surface of the external electrode on the side on which the mouth of the container is positioned; (c) a step of setting C:WRPrthbl\DCCUL\2932995_ .DOC.605/2010 - 12 gas pressure inside the plastic container, the chamber head, and the exhaust pipe to a predetermined value while gas inside and outside the container and the chamber head is discharged by the rotary vacuum sealing mechanism through 5 the exhaust pipe that includes a pipe portion made of a conductive material and a pipe portion made of an insulating material, and film-forming gas is discharged from the gas outlet into the container; and (d) a step of forming a coating film on the inner surface of the container by 10 applying an electric field between the external electrode and a ground electrode that includes the chamber head and the pipe portion made of a conductive material by the electric-field applying unit, generating plasma in the container, the chamber head, and the pipe portion made of a 15 conductive material, and dissociating the film-forming gas in the plasma. When the container is inserted in the external electrode, a spacer made of a dielectric material is interposed between at least the mouth and a shoulder of the container and the external electrode. 20 [0025] According to an embodiment of the present invention, a coating-film forming apparatus includes a film forming chamber for forming a coating film by plasma discharge on an inner surface of the container to be processed, the film-forming chamber including an external 25 electrode that has a hollow large enough to surround the container when the container is inserted therein; a conductive chamber head that is arranged through an insulating member on an end surface of the external electrode on a side on which a mouth of the container is 30 positioned, that is connected to an exhaust pipe, and that is grounded; a gas outlet that is inserted in the container in the external electrode from a side of the chamber head C:WRPonbl\DCCULu932995_ 1.DOC-6"512010 - 13 and that discharges film-forming gas; and an electric-field applying unit that applies an electric field between the external electrode and the chamber head and the exhaust pipe that are grounded, the exhaust pipe being made of a 5 conductive material, inside which an electric-field shielding member having air permeability and a conductive property is arranged at a position a desired distance away from the film-forming chamber, an area ratio (Sl/S2) between an area S1 of an inner surface of the external electrode in 10 which the container is housed and an area S2 of the ground electrode being equal to or more than one. [0026] Preferred embodiments of the invention provide a barrier-film forming apparatus capable of preventing instability of discharge and a power source failure due to a 15 relation with a rotary vacuum sealing mechanism and forming a barrier film such as a carbon film that has a good film quality on the inner surface of a plastic container at high speed in a plurality of film-making chambers communicated through exhaust pipes to the rotary vacuum sealing 20 mechanism. [0027] Also disclosed herein is a method of producing a plastic container capable of forming a barrier film such as a carbon film that has a good film quality on the inner surface of the plastic container good in barrier properties 25 against oxygen and carbon dioxide in the plurality of film forming chambers communicated through the exhaust pipes to the rotary vacuum sealing mechanism while preventing instability of discharge and a power source failure due to a relation with the rotary vacuum sealing mechanism.

C:\NRPorbDCC\IL\2932995-.DOC.6A)5/2010 -14 BRIEF DESCRIPTION OF DRAWINGS [0027A] The present invention will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 5 [0028] [Fig. 1] Fig. 1 is a plan view of a coating-film forming apparatus for forming a coating film on the inner surface of a container according to a first embodiment of the present invention; [Fig. 2] Fig. 2 is a cross section of a relevant part 10 that includes a film-forming chamber shown in Fig. 1; [Fig. 3] Fig. 3 is a cross section of a relevant part of another type of coating-film forming apparatus according to the first embodiment of the present invention; [Fig. 4] Fig. 4 is a cross section of a relevant part 15 of still another type of coating-film forming apparatus according to the first embodiment of the present invention; [Fig. 5] Fig. 5 is a graph of gas-barrier properties in Example 1 and Comparative Example 1 relating to an embodiment of the present invention; and 20 [Fig. 6] Fig. 6 is a cross section of a relevant part of a coating-film forming apparatus according to a second embodiment of the present invention. EXPLANATIONS OF LETTERS OR NUMERALS [0029] 1 Rotary vacuum sealing mechanism 25 2 Rotary disk 11 Exhaust pipe 12a Pipe portion made of a conductive material (Conductive pipe portion) 12b Pipe portion made of an insulating material (Insulating 30 pipe portion) 21 Film-forming chamber 27 External electrode C;.RPonbr\DCCUL\2932995_ .DOC.6"5/2010 - 14A 30 Cylindrical spacer 32 Chamber head 34 Gas supplying pipe 35 High-frequency power source 5 39 Honeycomb conductor (Electric-field shielding member having air permeability and conductive properties) 40 Layered metal mesh (Electric-field shielding member having air permeability and conductive properties) 41 Baffle (Electric-field shielding member having air 10 permeability and conductive properties) B Plastic bottle BEST MODE(S) FOR CARRYING OUT THE INVENTION [0030] A coating-film forming apparatus according to embodiments of the present invention is explained in detail 15 below with reference to the accompanying drawings. The present invention is not limited to the embodiments. [0031) (First Embodiment) Fig. 1 is a plan view of a coating-film forming 15 apparatus according to a first embodiment, and Fig. 2 is a cross section of a relevant part that includes a film forming chamber shown in Fig. 1. [0032] As shown in Fig. 1, a rotary vacuum sealing 5 mechanism 1 of the coating-film forming apparatus includes a rotary disk 2 on a fixed board (not shown) that rotates, for example, counterclockwise. A plurality of exhaust pipes 11 that are radially arranged are connected to an outer peripheral surface of the rotary disk 2, and film 10 forming chambers 21 are connected to tips of the exhaust pipes 11, respectively. In the rotary vacuum sealing mechanism 1, exhaust holes that correspond in number to the exhaust pipes 11 pass through the rotary disk 2. One ends of the exhaust holes communicate with the exhaust pipes 11, 15 and the other ends communicate through a predetermined number of long holes (for example, four long holes) passing through the fixed board with a vacuum pump (not shown) that has four levels of vacuum. A container that is an object to be processed (for 20 example, a plastic bottle: hereinafter, "plastic bottle B" in the embodiments) is carried to the film-forming chamber 21 positioned at a point S in Fig. 1 by a carrying device (not shown), and then stored therein. While the plastic bottle B is being rotated counterclockwise by the rotary 25 disk 2, a film is formed on the inner surface of the plastic bottle B in the film-forming chamber 21. At a point F in Fig. 1, the plastic bottle B inside which a barrier film as a coating film has been formed is taken out. From the point S to a barrier-film forming position just 30 before the point F, the level of vacuum in the film-forming chamber 21 is gradually increased in four levels from low to high to reach the level of vacuum suitable for forming a film.

16 (0033] Fig. 2 is a schematic diagram of the film-forming chamber 21. As shown in Fig. 2, the film-forming chamber 21 includes a cylindrical supporting member 24 made of a 5 conductive material that is mounted on a circular ring base 22 and that includes flanges 23a, and 23b on upper and lower ends, respectively. The film-forming chamber 21 extends from a chamber head 32 through the upper-end flange 23a. 10 A cylindrical external electrode body 25 made of a conductive material is arranged in the cylindrical supporting member 24. A disk-shaped external electrode bottom 26 made of a conductive material is detachably attached to a bottom of the external electrode body 25. 15 The external electrode body 25 and the external electrode bottom 26 form a cylindrical external electrode 27 that has a bottom and has a hollow large enough to place a plastic container (plastic bottle) B in which a barrier film (for example, a carbon film) is formed. A disk-shaped insulator 20 28 is arranged between the base 22 and the external electrode bottom 26. [0034] The external electrode bottom 26, the disk-shaped insulator 28, and the base 22 are integrally moved up and down with respect to the external electrode body 25 by a 25 pusher (not shown), so that the bottom of the external electrode body 25 is opened and closed. When the bottom is opened, the base 22, the insulator 28, and the external electrode bottom 26 can be removed in this order. When the bottom is closed, the external electrode bottom 26, the 30 insulator 28, and the base can be attached in reverse order. [0035] A cylindrical spacer 30 made of a dielectric material includes a hollow 29 that has a shape formed by a combination of a column and a truncated cone corresponding 17 to a mouse and a shoulder of the plastic bottle B to be inserted in the film-forming chamber 21. The cylindrical spacer 30 is arranged in an upper portion of the body 25. The spacer 30 is fixed by screws (not shown) via a 5 later-described ring-shaped insulating member arranged thereon. The ring-shaped insulating member 31 is arranged on an upper surface of the external electrode 27 such that an upper surface of the ring-shaped insulating member 31 is flush with the upper flange 23a of the cylindrical 10 supporting member 24. A hollow in the ring-shaped insulating member 31 has the same diameter as that of a portion of the hollow 29 at an upper end of the spacer 30 that the mouth of the plastic bottle B abuts. [0036] In this manner, the cylindrical spacer 30 is 15 arranged in an upper portion of the body 25 in the external electrode 27, and the ring-shaped insulating member 31 is fixed to the upper surfaces of the spacer 30 and the external electrode 27. Therefore, when the plastic bottle B is inserted in the external electrode body 25 through the 20 bottom, the upper end of the mouth of the plastic bottle B is accommodated in the hollow of the ring-shaped insulating member 31, the mouth and the shoulder of the plastic bottle B are accommodated in the hollow 29 of the spacer 30, and the rest part of the plastic bottle B is accommodated in 25 the external electrode 27. [0037] As a dielectric material that constitutes the cylindrical spacer 30, for example, plastic or ceramic that has a relative dielectric constant of 1.5 to 20 is cited. Various plastics can be used and particularly, it is 30 preferable, as plastic, to use fluorine resin such as polytetrafluoroethylene that is low in high-frequency loss (for example, tanO is 20X10~ 4 or less) and that has good heat resistance. It is preferable, as ceramic, to use 18 alumina or steatite that is low in high-frequency loss (for example, tanO is 20X10- 4 or less) or Macor that has high machinability. [0038] Next, the chamber head 32 that constitutes the 5 film-forming chamber 21 is explained. The rectangular block-shaped chamber head 32 made of a conductive material is connected to a discharge chamber 33, on its side, that is communicated with the exhaust pipe 11. The cylindrical supporting member 24 is hung through 10 the upper flange 23a from the chamber head 32 that is positioned on the upper surface of the ring-shaped insulating member 31, and is grounded. The chamber head 32 includes the discharge chamber 33 that is formed to have a substantially L-shape in section from a bottom surface to a 15 side surface (a left side surface in Fig. 2) of the member 32. A bottom side of the discharge chamber 33 is communicated with the hollow portion of the ring-shaped insulating member 31 (a mouse of a plastic bottle B when it is inserted). 20 [0039] A gas supplying pipe 34 serving as a gas outlet penetrates through the chamber head 32 and is inserted near a bottom of the plastic bottle B in the external electrode body 25 of the external electrode 27. The gas supplying pipe 34 can be made of a conductive 25 material like metal such as aluminum and stainless steel or made of an insulating material like ceramic such as alumina. When the gas supplying pipe 34 is made of a conductive material, because the gas supplying pipe 34 penetrates through the chamber head 32 that is grounded, the gas 30 supplying pipe 34 is also grounded with the chamber head 32. [0040] A high-frequency power source 35 that is an electric-field applying unit to impart an electric field between the external electrode 27 and a later-mentioned 19 ground electrode and that outputs high-frequency electric power, for example, with a frequency of 13.56 MHz is connected to a side surface of the body 25 of the external electrode 27 through a cable 36 and a power-feeding 5 terminal 37. A matching box 38 is arranged on the cable 36 between the high-frequency power source 35 and the power feeding terminal 37. [0041) The exhaust pipe 11 is made of a conductive material like metal such as stainless steel and is grounded 10 by connecting to the chamber head 32. [00421 A honeycomb conductor 39 of the present invention serving as an electric-field shielding member that has air permeability and conductive properties is arranged at a desired position inside the exhaust pipe 11. To arrange 15 the honeycomb conductor 39 at a desired position makes it possible to control a discharge area generated in the exhaust pipe 11 by the honeycomb conductor 39 and to prevent the discharge area from reaching the rotary vacuum sealing mechanism 1. This prevents instability of 20 discharge and a power source failure. [0043] By arranging the honeycomb conductor 39 in a different position in the exhaust pipe 11 (i.e., by changing the length of the exhaust pipe 11 effectively serving as a ground electrode), it is possible to control 25 an area ratio (Sl/S2) between the external electrode and the ground electrode. Sl is an area of an inner surface of the external electrode 27 in which a plastic container is accommodated. S2 is an area of the ground electrode, i.e., the area 30 obtained by adding an inner surface of the discharge chamber 33 of the chamber head 32 and an inner surface of the exhaust pipe 11 from the honeycomb conductor 39 to the chamber head 32. In addition, because the gas supplying 20 pipe 34 when being made of a conductive material functions as a ground electrode, an outer peripheral area of the gas supplying pipe 34 arranged in the chamber head 32 and in the external electrode 27 is also added to S2. 5 [0044] A method of producing a plastic container having coated with a barrier film on its inner surface by the barrier-film forming apparatus shown in Figs. 1 and 2 is explained. [0045] At the point S shown in Fig. 1, the base 22, the 10 external electrode bottom 26, and the disk-shaped insulator 28 of the film-forming chamber 21 are integrally removed by a pusher (not shown) to open the bottom of the electrode body 25. Then, a plastic bottle B is inserted through the open bottom side of the external electrode body 25 from its 15 mouth side. Thereafter, the external electrode bottom 26, the disk-shaped insulator 28, and the base 22 are integrally attached in its order by a pusher (not shown) to the bottom side of the external electrode body 25 to close the bottom of the external body 25. Thus, as shown in Fig. 20 2, the plastic bottle B is accommodated in such a manner that an upper end of its mouth abuts the hollow of the ring-shaped insulating member 31, the mouth and shoulder of the plastic bottle B abuts the hollow 29 of the spacer 30, and the rest part of the plastic bottle B abuts the 25 external electrode 27. The plastic bottle B is communicated with the discharge chamber 33 of the chamber head 32 through its mouth. [0046] The film-forming chamber 21 that accommodates the plastic bottle B is rotated counterclockwise by the rotary 30 disk 2 of the rotary vacuum sealing mechanism 1. In Fig. 1, during a time until reaching a barrier-film forming position that is just before a position F in which a plastic bottle having coated with a barrier film is taken 21 out, gas in the discharge chamber 33 of the chamber head 32 of the film-forming chamber 21 and inside and outside of the plastic bottle B is exhausted through the exhaust pipe 11, and the level of vacuum therein is gradually increased 5 from low to high in four zones in the rotary vacuum sealing mechanism 1. In Fig. 2, a barrier-film forming gas (for example, medium gas) is supplied to the gas supplying pipe 34 and is sent from its lower end into the plastic bottle B. The medium gas flows toward the mouth of the plastic bottle 10 B. Subsequently, while balancing a gas supplying amount and a gas exhaust amount, a gas pressure inside the plastic bottle B is set to a predetermined value. [0047] A high-frequency electric power, for example, with a frequency of 13.56 MHz is supplied from the high 15 frequency power source 35 to the body 25 of the external electrode 27 through the cable 36, the matching box 38, and the power-feeding terminal 37. Then, electric discharge occurs between the external electrode 27 and the chamber head 32 and part of the exhaust pipe 11 from a position at 20 which the honeycomb conductor 39 is arranged to the chamber head 32 that serve as a ground electrode and plasma is generated. The generation of plasma causes a medium gas to be dissociated in the plasma and film-forming ions are accumulated on the inner surface of the plastic bottle B in 25 the external electrode 27. Therefore, a carbon film as a barrier film that has a good film quality is formed at high speed, so that a plastic bottle having coated with a barrier film on its inner surface is formed. When the film-forming chamber 21 reaches the point F by rotating the 30 rotary disk 2 of the rotary vacuum sealing mechanism 1, the plastic bottle having coated with a barrier film on its inner surface is taken out. When the gas supplying pipe 34 is made of a conductive material, it serves as a ground 22 electrode. [0048] Examples of the medium gas mainly inclusive of hydrocarbon include alkane groups such as methane, ethane, propane, butane, pentane, and hexane; alkene groups such as 5 ethylene, propylene, butene, pentene, and butadiene; alkine groups such as acethylene; aromatic hydrocarbon groups such as benzene, toluene, xylene, indene, naphthaline, and phenanthrene; cycloparaffin groups such as cyclopropane and cyclohexane; cycloolefin groups such as cyclopentene and 10 cyclohexene; oxygenerated hydrocarbon groups such as methanol and ethanol; nitrogen-containing hydrocarbon groups such as methylamine, ethylamine, and aniline. In addition to them, carbon monoxide and carbon dioxide can also be used. A noble gas such as Ar and He can be mixed 15 with the medium gas to stabilize plasma and to make plasma characteristics appropriate. [0049] As the barrier-film forming gas, in addition to the medium gas, gas mixed with siloxane such as hexamethyldisiloxane and oxygen to form a film that 20 includes SiOx can be used. [0050] The high-frequency electric power with a frequency of 13.56 MHz and 100 W to 1000 W is generally used but the high-frequency electric power is not limited thereto. The electric power can be applied consecutively 25 or intermittently (like a pulse form). [0051] When a barrier film is formed on the inner surface of the plastic bottle B, it is desirable to control the area ratio (Sl/S2) between the area (Sl) of the inner surface of the external electrode 27 in which the plastic 30 bottle B is housed and the area (S2) of the ground electrode to be equal to or more than one. In other words, to change a position of arranging the honeycomb conductor 39 in the exhaust pipe 11 means to change the length of the 23 exhaust pipe 11 effectively serving as a ground electrode. By controlling the area ratio (S2/Sl) to be a desired area ratio, the discharge area can be controlled. However, when the area ratio (S2/Sl) increases more than needed, barrier 5 properties of the barrier film formed on the inner surface of the plastic bottle may decrease due to an excessive increase of the discharge area and a decrease of power efficiency. Therefore, an upper limit of the area ratio (S2/Sl) is preferably five. The upper limit of the area 10 ratio (S2/Sl) is more preferably 3.5. [0052] As described above, according to the first embodiment, when the plastic bottles B are accommodated in the plurality of film-forming chambers 21 connected through the exhaust pipes 11 to the rotary disk 2 of the rotary 15 vacuum sealing mechanism 1 and a barrier film is consecutively formed on the inner surface of each plastic bottle B, the honeycomb conductor 39 as an electric-field shielding member having air permeability and conductive properties is arranged in the exhaust pipe 11, and not only 20 the chamber head 32 made of a conductive material but also part of the exhaust pipe 11 that includes from the position at which the honeycomb conductor 39 is arranged to the chamber head 32 function as the ground electrode, so that the discharge area is extended from the chamber head 32 to 25 the exhaust pipe 11 communicated therewith. Thus, a large plasma sheath voltage can be applied between the external electrode 27 and the ground electrode that includes the chamber head 32 and part of the exhaust pipe 11 and positive ions with high energy generated from the barrier 30 film forming gas such as the medium gas dissociated in plasma reaches the inner surface of the plastic bottle B, thereby forming a barrier film that has a good film quality such as a carbon film on the inner surface of the plastic 24 bottle B at high speed. [00531 The honeycomb conductor 39 is arranged at a desired position inside the exhaust pipe 11 made of a conductive material, so that the discharge area generated 5 in the exhaust pipe 11 is controlled by the honeycomb conductor 39 and is prevented from reaching the rotary vacuum sealing mechanism 1, thereby preventing instability of discharge and a power source failure. [0054] The discharge area generated in the exhaust pipe 10 11 can be controlled by the honeycomb conductor 39 and is prevented from reaching the rotary vacuum sealing mechanism 1, so that mutual interference with electric discharge (plasma) reaching the rotary vacuum sealing mechanism from another adjacent film-forming chamber is prevented, thereby 15 preventing instability of discharge and a power source failure. [0055] By arranging the honeycomb conductor 39 at a different position of the exhaust pipe 11 (i.e., by changing the length of the exhaust pipe 11 effectively 20 serving as the ground electrode), the area ratio (S2/Sl) between the area (Sl) of the inner surface of the external electrode 27 in which the plastic bottle is accommodated and the area (S2) of the ground electrode is controlled to be equal to or more than one, thereby forming a barrier 25 film that has a good film quality such as a carbon film on the inner surface of the plastic bottle B at high speed. [0056] The cylindrical spacer 30 made of a dielectric material that includes the hollow 29 is arranged in and fixed to an upper portion of the external electrode 27. At 30 least a portion from the mouth to the shoulder of the plastic bottle B is housed in the hollow 29 of the spacer 30 in such a manner that it abuts an inner surface of the spacer 30. Therefore, a barrier film such as a carbon film CARPorbl\DCCU L\2932995 I.DOC-6S/20I10 -25 that has a good film quality can be formed to have a uniform thickness not only on a part of the inner surface of the plastic bottle B from its shoulder to its body below the shoulder but also on a part of the inner surface from its 5 mouth to its shoulder that corresponds to the spacer 30 made of the dielectric material. [0057] Consequently, it is possible to provide the highly-reliable apparatus that can form a barrier film having a good film quality such as a carbon film at high 10 speed on the inner surface of the plastic container such as the plastic bottle B. [0058] It is possible to manufacture a plastic bottle having coated with a barrier film with high barrier properties on its inner surface so that oxygen from outside 15 of the plastic bottle is prevented from permeating and carbon dioxide from inside of the plastic bottle (for example, carbonated drinks) is prevented from emitting. [0059] The barrier film includes a soft carbon film that has more graphite (carbon atom bonding is SP 2 bonding) in 20 compound than diamond (carbon atom bonding is SP 3 bonding) and that has a hardness equal to or less than 10 GPa in a micro hardness measuring method and a hard carbon film that has less graphite in compound because of higher discharge voltage and that has a hardness of 10 to 20 GPa in the micro 25 hardness measuring method, i.e., a diamond-like carbon film (a DLC film). In addition, a SiO 2 film or a SiOx film is also included. A film is also included in which they are mixed with a different type of atom such as C, a metal atom, N, and 0 in a ratio of about a ultralow amount to a few %. 30 Here, the barrier film is used as an example and a film formed for the purpose of improving chemical resistance and abrasion resistance is also included as a coating film.

C:\RPonbNDCCUlL\932995. DOC.6A5/2010 -26 [0060] A glass container, a ceramic container, a paper container, and the like can be exemplified besides the plastic container represented as a plastic bottle having coated with a barrier film on its inner surface. 5 [0061] As the container, a plastic container filled with volatile liquid such as carbonated drinks and a plastic fuel container for a vehicle that is filled with fuel can be cited. Besides the containers, for example, a plastic container for medical goods and a plastic container for food 10 can be cited. In addition, a gas container for containing gas, which has high permeability, that needs a gas-barrier properties, can be cited. Embodiments of the present invention can be also applied to a plastic pipe when coating its inner surface like the container. 15 [0062] According to the first embodiment, the honeycomb conductor is arranged in the exhaust pipe 11 as an electric field shielding member having air permeability and conductive properties. Various types of honeycomb conductors can be used as described below with reference to 20 Figs. 3 and 4. The same components in Figs. 3 and 4 as those in Fig. 2 are given the same reference characters and the explanation thereof is omitted. [0063] Fig. 3 is a cross section of a relevant part of another type of coating-film forming apparatus according to 25 the first embodiment of the present invention. (1) As shown in Fig. 3, a metal mesh 40 that is formed by laminating a plurality of, for example, three electric field shielding members each of which has air permeability and conductive properties is arranged at a desired position 30 in the exhaust pipe 11. Under this configuration, by changing the position of arranging the layered metal mesh 40 in the exhaust pipe 11 (i.e., by changing the length of the C:\NRPorNbL\DCCMLU2995_ DOC6/05/2010 -27 exhaust pipe 11 effectively serving as a ground electrode), it is possible to control the area ratio (S2/Sl) between the external electrode and the ground electrode. The area ratio (S2/S1) is preferably equal to or more than one. Note that 5 the upper limit of the area ratio (S2/Sl) is preferably five in view of a decrease in barrier properties of a barrier film formed on the inner surface of the plastic bottle due to excessive extension of the discharge area. [0064] Fig. 4 is a cross section of a relevant part of 10 still another type of coating-film forming apparatus according to the first embodiment of the present invention. (2) As shown in Fig. 4, a baffle 41 made of a conductive material as an electric-field shielding member that has air permeability and a conductive material is 15 arranged at a desired position in the exhaust pipe 11. Under this configuration, by changing the position of arranging the baffle 41 in the exhaust pipe 11 (i.e., by changing the length of the exhaust pipe 11 effectively serving as a ground electrode), it is possible to control 20 the area ratio (S2/Sl) between the external electrode and the ground electrode. The area ratio (52/51) will be equal to or more than one. Note that the upper limit of the area ratio (S2/Sl) is preferably five in view of a decrease in barrier properties of a barrier film formed on the inner 25 surface of the plastic bottle due to excessive extension of the discharge area, as described above. [0065] Specific examples according to the first embodiment of the present invention are explained below. However, the present invention is not limited to the 28 examples. (Example 1) By using the barrier-film forming apparatus shown in Figs. 1 and 2, a carbon film was formed on the inner 5 surface of a plastic bottle B. The plastic bottle B was set such that the upper end of the mouth of the plastic bottle B was accommodated in the hollow of the ring-shaped insulating member 31, the mouth and shoulder of the plastic bottle B were accommodated in the hollow 29 of the spacer 10 30, and the rest part of the plastic bottle B was accommodated in the external electrode 27. The position of the honeycomb conductor 39 was changed in the exhaust pipe 11 to control the area ratio (S2/Sl) between the area (Sl) of the inner surface of the external electrode 27 in which 15 the plastic bottle B was housed and the area (S2) of the ground electrode. With the gas supplying pipe 34 made of aluminum, a carbon film was formed on the inner surface of the plastic bottle B based on the following conditions: [0066] <Conditions for forming a carbon film> 20 e Cylindrical spacer 30: made of Photoveel (product name, manufactured by Sumikin Ceramics & Quartz Co.,Ltd.) " Area ratio (S2/S1)=1 to 3.5 " Medium: C 2

H

2 gas e Gas flow of the medium: 124 sccm 25 e Gas pressure in the plastic bottle B and the chamber head 32: 0.3 Torr e High-frequency electric power supplied to the external electrode 27: 13 MHz, 1600 W * Film-forming time: 3 seconds 30 [0067] (Comparative Example 1) By using the barrier-film forming apparatus shown in Figs. 1 and 2, a carbon film was formed on the inner 29 surface of a plastic bottle B. The plastic bottle B was set such that the upper end of the mouth of the plastic bottle B was accommodated in the hollow of the ring-shaped insulating member 31, the mouth and shoulder of the plastic 5 bottle B were accommodated in the hollow 29 of the spacer 30, and the rest part of the plastic bottle B was accommodated in the external electrode 27. The honeycomb conductor was arranged at a corner located at a start of the chamber head 32 towards the exhaust pipe 11 such that 10 the exhaust pipe 11 did not function as a discharge area. A carbon film was formed on the inner surface of the plastic bottle in the same manner as in Example 1 except that the area ratio (S2/Sl) between the area (Sl) of the inner surface of the external electrode 27 and the area 15 (S2) of the ground electrode was set to 0.7. [0068] A sample of 30 cm2 was cut out of a body portion of the plastic bottle B in which a carbon film had been formed based on a different value of the area ratio (S2/Sl) in Example 1 and in Comparative Example 1. Then, the 20 oxygen permeability of the sample was measured by using an oxygen permeability measuring apparatus (manufactured by Modern Control Co., Ltd, product name: OXTRAN) and relative oxygen barrier properties were obtained based on the oxygen permeability converted into a carbon film of 20 nm in 25 thickness. The results are shown in Fig. 5. [0069] As shown in Fig. 5, it is apparent that, compared with Comparative Example 1 in which the exhaust pipe 11 does not function as the discharge area and the area ratio (S2/Sl) is set to 0.7, a carbon film that has a good gas 30 barrier properties, i.e., good film properties can be formed on the inner surface of the plastic bottle B in Example 1 in which the exhaust pipe 11 effectively functions as the discharge area and the area ratio (Sl/S2) C:\NRPoblDCClt\932995 1 DOC-A5/2010 -30 between the area (Si) of the inner surface of the external electrode 27 and the area (S2) of the ground electrode is equal to or more than one. [0070] (Second Embodiment) 5 A barrier-film forming apparatus for forming a barrier film on the inner surface of a plastic container according to a second embodiment substantially has the same configuration as that in Figs. 1 and 2 as described above except that the apparatus has a different configuration of the exhaust pipe as shown in Fig. 6. 10 The same components as those in the first embodiment are given the same signs and numerals and the explanation thereof is omitted. [0071] As shown in Fig. 6, the exhaust pipe 11 of the barrier film forming apparatus includes a pipe portion (a conductive pipe portion) 12a and a pipe portion 12b (an insulating pipe portion) 15 that are connected to each other. The pipe portion 12a is made of a conductive material like metal such as stainless steel. The pipe portion 12b is made of an insulating material like synthetic resin such as polypropylene and like ceramic such as alumina. The conductive pipe portion 12a is connected to a side of the chamber 20 head 32 of the film-forming chamber 21 to communicate with the discharge chamber 33 of the member 32. The insulating pipe portion 12b is connected to the rotary disk 2 of the rotary vacuum sealing mechanism 1. [0072] By changing the length of the conductive pipe 25 portion 12a that corresponds to part of the exhaust pipe 11 (i.e., by changing the length of the exhaust pipe 11 effectively serving as a ground electrode), it is possible to control the area ratio (S2/S1) between the area (S1) of the inner surface of the external electrode 27 in which a plastic bottle B is housed and 30 the area (S2) of the ground electrode. The area ratio (S2/S1) will be equal to 31 or more than one. Note that the upper limit of the area ratio (S2/Sl) is preferably 5, more preferably 3.5, in view of a decrease in barrier properties of a barrier film formed on the inner surface of the plastic bottle due to 5 excessive extension of a discharge area as described above. [0073] According to the second embodiment, when plastic bottles B are accommodated in the plurality of film-forming chambers 21 connected through the exhaust pipes 11, each of which includes the conductive pipe portion 12a and the 10 insulating pipe portion 12b, to the rotary disk 2 of the rotary vacuum sealing mechanism 1 shown in Fig. 1 and a barrier film is consecutively formed on the inner surface of each plastic bottle B, the conductive pipe portion 12a is connected to the side of the chamber head 32 of the 15 film-forming chamber 21 to communicate with the discharge chamber 33 of the member 32, and not only the chamber head 32 made of a conductive material but also the conductive pipe portion 12a of the exhaust pipe 11 functions as a ground electrode to extend the discharge area from the 20 chamber head 32 to the conductive pipe portion 12a of the exhaust pipe 11 communicated therewith. Hence, a large plasma sheath voltage can be applied between the external electrode 27 and the ground electrode that includes the chamber head 32 and part of the exhaust pipe 11, so that 25 positive ions with high energy generated from a barrier film forming gas such as a medium gas dissociated in plasma can be entered to the inner surface of the plastic bottle B, thereby forming a barrier film such as a carbon film that has a good film quality at high speed on the inner surface 30 of the plastic bottle B. [0074] The exhaust pipe 11 includes the conductive pipe portion 12a and the insulating pipe portion 12b, so that the discharge area can be contained in the conductive pipe 32 portion 12a of the exhaust pipe 11 and be prevented from reaching the rotary vacuum sealing mechanism 1. This makes it possible to prevent instability of discharge and a power source failure. 5 [0075] By changing the length of the conductive pipe portion 12a that corresponds to part of the exhaust pipe 11 (i.e., by changing the length of the exhaust pipe 11 effectively serving as a ground electrode), the area ratio (S2/Sl) between the area (Sl) of the inner surface of the 10 external electrode 27 in which the plastic bottle B is housed and the area (S2) of the ground electrode is controlled to be equal to or more than one. Therefore, a barrier film having good film properties such as a carbon film can be formed on the inner surface of the plastic 15 bottle B at high speed. [0076] According to the second embodiment, it is possible to provide the barrier-film forming apparatus that can form a barrier film having good film properties such as a carbon film on the inner surface of the plastic container 20 such as the plastic bottle B with high reliability at high speed in the same manner as the first embodiment. [0077] Furthermore, it is possible to manufacture a plastic bottle having coated with a barrier film on its inner surface that prevents oxygen from permeating from 25 outside and carbon dioxide from emitting from inside (for example, carbonated drinks) and that is excellent in barrier properties. [0078] A specific example according to the second embodiment of the present invention is explained below. 30 However, the present invention is not limited to the example. (Example 2) By using the barrier-film forming apparatuses shown in 33 Figs. 1 and 6, a carbon film was formed on the inner surface of a plastic bottle B. The plastic bottle B was set such that the upper end of the mouth of a plastic bottle B was accommodated in the hollow of the ring-shaped 5 insulating member 31, the mouth and shoulder of the plastic bottle B were accommodated in the hollow 29 of the spacer 30, and the rest part of the plastic bottle B was accommodated in the external electrode 27. The conductive pipe portion 12a constituting the exhaust pipe 11 was 10 changed in length to control the area ratio (S2/Sl) between the area (Sl) of the inner surface of the external electrode 27 in which the plastic bottle B was housed and the area (S2) of the ground electrode. With the gas supplying pipe 34 made of aluminum, a carbon film was 15 formed on the inner surface of the plastic bottle B based on the following conditions: [0079] <Conditions for forming a carbon film> * Cylindrical spacer 30: made of Photoveel (product name, manufactured by Sumikin Ceramics & Quartz Co.,Ltd.) 20 9 Area ratio (S2/Sl)=l to 3.5 * Medium: C 2

H

2 gas " Gas flow of the medium: 124 sccm " Gas pressure in the plastic bottle B and the chamber head 32: 0.3 Torr 25 e High-frequency electric power supplied to the external electrode 27: 13 MHz, 1600 W e Film-forming time: 3 seconds [0080] A sample of 30 cm 2 was cut out of a body portion of the plastic bottle B in which a carbon film had been 30 formed based on a different value of the area ratio (S2/Sl) in Example 2. The oxygen permeability of the sample was measured by using an oxygen permeability measuring C:\NR onblDCC\L\2932995_l.OCV5/20 10 -34 apparatus (manufactured by Modern Control Co., Ltd, product name: OXTRAN) and relative oxygen barrier properties were obtained based on the oxygen permeability converted into a carbon film of 20 nm in thickness. As a result, likewise 5 the first embodiment, a carbon film having a good gas barrier properties, i.e., a good film quality was formed on the inner surface of the plastic bottle B, compared with the case where the exhaust pipe 11 did not function as the discharge area. 10 [0081] The gas supplying pipe 34 made of aluminum is used in the Examples 1 and 2. Even if it is replaced with a gas supplying pipe made of ceramic such as alumina, a carbon film that has a good film quality comparable with that of the gas supplying pipe made of aluminum can be also formed, 15 though it has a little lower gas-barrier properties, on the inner surface of the plastic bottle B. This is because the gas supplying pipe made of ceramic does not function as a ground electrode and the area ratio (S2/Sl) is slightly smaller. 20 [0082] The high-frequency power source connected to the external electrode is used as an electric-field applying unit in the first and second embodiments. However, for example, a bias power source connected to the external electrode and a high-frequency power source connected to the 25 gas supplying pipe (an internal electrode) can constitute an electric-field applying unit and a gas exhaust pipe can have a ground potential. This configuration enables the speed of forming a carbon film as a barrier film to increase. [0083] The barrier-film forming apparatus for forming a 30 coating film on the inner surface of the container embodying the present invention is explained above as using the film forming chamber 21 shown in Fig. 2. A film-forming chamber C.\NRPonb\DCC\!L\2932995_LDOC wM5/2010 -35 is not limited to the film-forming chamber 21. For example, if plasma spreads in the exhaust pipe 11 through which the rotary vacuum sealing mechanism 1 and the film-forming chamber 21 are communicated with each other, any film 5 forming chamber can be applied. In the above description of the present invention, a coating film is formed on the inner surface of the container in the film-forming chamber. However, a coating film can be formed on the outer surface of a container as well as on the inner surface in the film 10 forming chamber. [0084] As described above, it is possible to provide a barrier-film forming apparatus for forming a barrier film on the inner surface of a plastic container. The barrier-film forming apparatus is excellent in mass-producing barrier 15 films having a good film quality such as a carbon film on an inner surface of plastic containers at high speed in a plurality of film-forming chambers that are communicated through exhaust pipes with a rotary vacuum sealing mechanism, and is capable of preventing instability of 20 discharge and a power source failure due to a relation with the rotary vacuum sealing mechanism. [0085] It is possible to provide a corresponding method that is useful for producing a plastic container, such as a plastic bottle of beverage, in which a barrier film having a 25 good film quality such as a carbon film and excellent in barrier properties against oxygen and carbon dioxide is formed in a plurality of film-forming chambers that are communicated through exhaust pipes with a rotary vacuum sealing mechanism, and is capable of preventing instability 30 of discharge and a power source failure due to a relation with the rotary vacuum sealing mechanism. [0086] Many modifications will be apparent to those C:\NRPonbrDCCUL\2932995 1.DOC-6A)5/2010 -36 skilled in the art without departing from the scope of the present invention. [0087] Throughout this specification and the claims which follow, unless the context requires otherwise, the word 5 "comprise", and variations such as "comprises" and "comprising", will be understood to imply the inclusion of a stated integer or step or group of integers or steps but not the exclusion of any other integer or step or group of integers or steps. 10 [0088] The reference in this specification to any prior publication (or information derived from it), or to any matter which is known, is not, and should not be taken as an acknowledgment or admission or any form of suggestion that that prior publication (or information derived from it) or 15 known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims

1. An apparatus for forming a coating film on an inner surface of a container, comprising: 5 a film-forming chamber for forming a coating film by plasma discharge on an inner surface of a container to be processed, wherein the film-forming chamber includes an external electrode that has a hollow large enough to 10 surround the container when the container is inserted therein; a conductive chamber head that is arranged through an insulating member on an end surface of the external electrode on a side on which a mouth of the container is positioned, that is connected to an exhaust pipe, and that is grounded; 15 a gas outlet that is inserted in the container in the external electrode from a side of the chamber head, and that discharges film-forming gas; and an electric-field applying unit that applies an electric field between the external electrode and the chamber head 20 and the exhaust pipe that are grounded, wherein the exhaust pipe is made of a conductive material, inside which an electric-field shielding member having air permeability and a conductive property is arranged at a position a desired distance away from the film-forming chamber, and 25 the desired distance is set such that an area ratio (S2/Sl) between an area Si of an inner surface of the external electrode in which the container is housed and an area S2 of the ground electrode constituted by the chamber head, the exhaust pipe made of the conductive material, and the electric-field shielding 30 member, is equal to or more than one.

2. The apparatus according to claim 1, wherein the electric- C:NRPonbrDCCLU932995 .DOC.45/2010 - 38 field shielding member has any one of a honeycomb structure and a mesh structure.

3. The apparatus according to claim 1, wherein the area ratio 5 (S2/Sl) is set to be equal to or less than five.

4. The apparatus according to any one of claims 1 to 3, wherein a plurality of film-forming chambers are provided and the film forming chambers communicate with a rotary vacuum sealing 10 mechanism through the exhaust pipe.

5. The apparatus according to any one of claims 1 to 4, wherein the coating film is a barrier film. 15

6. An apparatus for forming a coating film on an inner surface of a container, substantially as hereinbefore described with reference to the accompanying drawings.